for Journals by Title or ISSN
for Articles by Keywords
help

Publisher: John Wiley and Sons   (Total: 1576 journals)

 A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  

        1 2 3 4 5 6 7 8 | Last   [Sort by number of followers]   [Restore default list]

Showing 1 - 200 of 1576 Journals sorted alphabetically
Abacus     Hybrid Journal   (Followers: 12, SJR: 0.48, h-index: 22)
About Campus     Hybrid Journal   (Followers: 5)
Academic Emergency Medicine     Hybrid Journal   (Followers: 58, SJR: 1.385, h-index: 91)
Accounting & Finance     Hybrid Journal   (Followers: 46, SJR: 0.547, h-index: 30)
ACEP NOW     Free   (Followers: 1)
Acta Anaesthesiologica Scandinavica     Hybrid Journal   (Followers: 51, SJR: 1.02, h-index: 88)
Acta Archaeologica     Hybrid Journal   (Followers: 139, SJR: 0.101, h-index: 9)
Acta Geologica Sinica (English Edition)     Hybrid Journal   (Followers: 3, SJR: 0.552, h-index: 41)
Acta Neurologica Scandinavica     Hybrid Journal   (Followers: 5, SJR: 1.203, h-index: 74)
Acta Obstetricia et Gynecologica Scandinavica     Hybrid Journal   (Followers: 15, SJR: 1.197, h-index: 81)
Acta Ophthalmologica     Hybrid Journal   (Followers: 5, SJR: 0.112, h-index: 1)
Acta Paediatrica     Hybrid Journal   (Followers: 56, SJR: 0.794, h-index: 88)
Acta Physiologica     Hybrid Journal   (Followers: 6, SJR: 1.69, h-index: 88)
Acta Polymerica     Hybrid Journal   (Followers: 9)
Acta Psychiatrica Scandinavica     Hybrid Journal   (Followers: 35, SJR: 2.518, h-index: 113)
Acta Zoologica     Hybrid Journal   (Followers: 6, SJR: 0.459, h-index: 29)
Acute Medicine & Surgery     Hybrid Journal   (Followers: 2)
Addiction     Hybrid Journal   (Followers: 33, SJR: 2.086, h-index: 143)
Addiction Biology     Hybrid Journal   (Followers: 12, SJR: 2.091, h-index: 57)
Adultspan J.     Hybrid Journal   (SJR: 0.127, h-index: 4)
Advanced Energy Materials     Hybrid Journal   (Followers: 24, SJR: 6.411, h-index: 86)
Advanced Engineering Materials     Hybrid Journal   (Followers: 26, SJR: 0.81, h-index: 81)
Advanced Functional Materials     Hybrid Journal   (Followers: 50, SJR: 5.21, h-index: 203)
Advanced Healthcare Materials     Hybrid Journal   (Followers: 13, SJR: 0.232, h-index: 7)
Advanced Materials     Hybrid Journal   (Followers: 250, SJR: 9.021, h-index: 345)
Advanced Materials Interfaces     Hybrid Journal   (Followers: 6, SJR: 1.177, h-index: 10)
Advanced Optical Materials     Hybrid Journal   (Followers: 5, SJR: 2.488, h-index: 21)
Advanced Science     Open Access   (Followers: 5)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17, SJR: 2.729, h-index: 121)
Advances in Polymer Technology     Hybrid Journal   (Followers: 13, SJR: 0.344, h-index: 31)
Africa Confidential     Hybrid Journal   (Followers: 19)
Africa Research Bulletin: Economic, Financial and Technical Series     Hybrid Journal   (Followers: 12)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 9)
African Development Review     Hybrid Journal   (Followers: 35, SJR: 0.275, h-index: 17)
African J. of Ecology     Hybrid Journal   (Followers: 15, SJR: 0.477, h-index: 39)
Aggressive Behavior     Hybrid Journal   (Followers: 15, SJR: 1.391, h-index: 66)
Aging Cell     Open Access   (Followers: 10, SJR: 4.374, h-index: 95)
Agribusiness : an Intl. J.     Hybrid Journal   (Followers: 6, SJR: 0.627, h-index: 14)
Agricultural and Forest Entomology     Hybrid Journal   (Followers: 14, SJR: 0.925, h-index: 43)
Agricultural Economics     Hybrid Journal   (Followers: 44, SJR: 1.099, h-index: 51)
AIChE J.     Hybrid Journal   (Followers: 29, SJR: 1.122, h-index: 120)
Alcoholism and Drug Abuse Weekly     Hybrid Journal   (Followers: 7)
Alcoholism Clinical and Experimental Research     Hybrid Journal   (Followers: 7, SJR: 1.416, h-index: 125)
Alimentary Pharmacology & Therapeutics     Hybrid Journal   (Followers: 34, SJR: 2.833, h-index: 138)
Alimentary Pharmacology & Therapeutics Symposium Series     Hybrid Journal   (Followers: 3)
Allergy     Hybrid Journal   (Followers: 50, SJR: 3.048, h-index: 129)
Alternatives to the High Cost of Litigation     Hybrid Journal   (Followers: 3)
American Anthropologist     Hybrid Journal   (Followers: 128, SJR: 0.951, h-index: 61)
American Business Law J.     Hybrid Journal   (Followers: 24, SJR: 0.205, h-index: 17)
American Ethnologist     Hybrid Journal   (Followers: 91, SJR: 2.325, h-index: 51)
American J. of Economics and Sociology     Hybrid Journal   (Followers: 27, SJR: 0.211, h-index: 26)
American J. of Hematology     Hybrid Journal   (Followers: 31, SJR: 1.761, h-index: 77)
American J. of Human Biology     Hybrid Journal   (Followers: 12, SJR: 1.018, h-index: 58)
American J. of Industrial Medicine     Hybrid Journal   (Followers: 16, SJR: 0.993, h-index: 85)
American J. of Medical Genetics Part A     Hybrid Journal   (Followers: 15, SJR: 1.115, h-index: 61)
American J. of Medical Genetics Part B: Neuropsychiatric Genetics     Hybrid Journal   (Followers: 3, SJR: 1.771, h-index: 107)
American J. of Medical Genetics Part C: Seminars in Medical Genetics     Partially Free   (Followers: 5, SJR: 2.315, h-index: 79)
American J. of Physical Anthropology     Hybrid Journal   (Followers: 36, SJR: 1.41, h-index: 88)
American J. of Political Science     Hybrid Journal   (Followers: 250, SJR: 5.101, h-index: 114)
American J. of Primatology     Hybrid Journal   (Followers: 15, SJR: 1.197, h-index: 63)
American J. of Reproductive Immunology     Hybrid Journal   (Followers: 3, SJR: 1.347, h-index: 75)
American J. of Transplantation     Hybrid Journal   (Followers: 16, SJR: 2.792, h-index: 140)
American J. on Addictions     Hybrid Journal   (Followers: 9, SJR: 0.843, h-index: 57)
Anaesthesia     Hybrid Journal   (Followers: 120, SJR: 1.404, h-index: 88)
Analyses of Social Issues and Public Policy     Hybrid Journal   (Followers: 11, SJR: 0.397, h-index: 18)
Analytic Philosophy     Hybrid Journal   (Followers: 16)
Anatomia, Histologia, Embryologia: J. of Veterinary Medicine Series C     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 27)
Anatomical Sciences Education     Hybrid Journal   (Followers: 1, SJR: 0.633, h-index: 24)
Andrologia     Hybrid Journal   (Followers: 2, SJR: 0.528, h-index: 45)
Andrology     Hybrid Journal   (Followers: 2, SJR: 0.979, h-index: 14)
Angewandte Chemie     Hybrid Journal   (Followers: 161)
Angewandte Chemie Intl. Edition     Hybrid Journal   (Followers: 209, SJR: 6.229, h-index: 397)
Animal Conservation     Hybrid Journal   (Followers: 35, SJR: 1.576, h-index: 62)
Animal Genetics     Hybrid Journal   (Followers: 8, SJR: 0.957, h-index: 67)
Animal Science J.     Hybrid Journal   (Followers: 6, SJR: 0.569, h-index: 24)
Annalen der Physik     Hybrid Journal   (Followers: 5, SJR: 1.46, h-index: 40)
Annals of Anthropological Practice     Partially Free   (Followers: 2, SJR: 0.187, h-index: 5)
Annals of Applied Biology     Hybrid Journal   (Followers: 8, SJR: 0.816, h-index: 56)
Annals of Clinical and Translational Neurology     Open Access   (Followers: 1)
Annals of Human Genetics     Hybrid Journal   (Followers: 9, SJR: 1.191, h-index: 67)
Annals of Neurology     Hybrid Journal   (Followers: 44, SJR: 5.584, h-index: 241)
Annals of Noninvasive Electrocardiology     Hybrid Journal   (Followers: 2, SJR: 0.531, h-index: 38)
Annals of Public and Cooperative Economics     Hybrid Journal   (Followers: 9, SJR: 0.336, h-index: 23)
Annals of the New York Academy of Sciences     Hybrid Journal   (Followers: 5, SJR: 2.389, h-index: 189)
Annual Bulletin of Historical Literature     Hybrid Journal   (Followers: 12)
Annual Review of Information Science and Technology     Hybrid Journal   (Followers: 14)
Anthropology & Education Quarterly     Hybrid Journal   (Followers: 24, SJR: 0.72, h-index: 31)
Anthropology & Humanism     Hybrid Journal   (Followers: 16, SJR: 0.137, h-index: 3)
Anthropology News     Hybrid Journal   (Followers: 14)
Anthropology of Consciousness     Hybrid Journal   (Followers: 11, SJR: 0.172, h-index: 5)
Anthropology of Work Review     Hybrid Journal   (Followers: 11, SJR: 0.256, h-index: 5)
Anthropology Today     Hybrid Journal   (Followers: 93, SJR: 0.545, h-index: 15)
Antipode     Hybrid Journal   (Followers: 45, SJR: 2.212, h-index: 69)
Anz J. of Surgery     Hybrid Journal   (Followers: 6, SJR: 0.432, h-index: 59)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apmis     Hybrid Journal   (Followers: 1, SJR: 0.855, h-index: 73)
Applied Cognitive Psychology     Hybrid Journal   (Followers: 67, SJR: 0.754, h-index: 69)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7, SJR: 0.632, h-index: 58)
Applied Psychology     Hybrid Journal   (Followers: 136, SJR: 1.023, h-index: 64)
Applied Psychology: Health and Well-Being     Hybrid Journal   (Followers: 48, SJR: 0.868, h-index: 13)
Applied Stochastic Models in Business and Industry     Hybrid Journal   (Followers: 5, SJR: 0.613, h-index: 24)
Aquaculture Nutrition     Hybrid Journal   (Followers: 14, SJR: 1.025, h-index: 55)
Aquaculture Research     Hybrid Journal   (Followers: 31, SJR: 0.807, h-index: 60)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 34, SJR: 1.047, h-index: 57)
Arabian Archaeology and Epigraphy     Hybrid Journal   (Followers: 11, SJR: 0.453, h-index: 11)
Archaeological Prospection     Hybrid Journal   (Followers: 12, SJR: 0.922, h-index: 21)
Archaeology in Oceania     Hybrid Journal   (Followers: 13, SJR: 0.745, h-index: 18)
Archaeometry     Hybrid Journal   (Followers: 27, SJR: 0.809, h-index: 48)
Archeological Papers of The American Anthropological Association     Hybrid Journal   (Followers: 14, SJR: 0.156, h-index: 2)
Architectural Design     Hybrid Journal   (Followers: 25, SJR: 0.261, h-index: 9)
Archiv der Pharmazie     Hybrid Journal   (Followers: 4, SJR: 0.628, h-index: 43)
Archives of Drug Information     Hybrid Journal   (Followers: 4)
Archives of Insect Biochemistry and Physiology     Hybrid Journal   (SJR: 0.768, h-index: 54)
Area     Hybrid Journal   (Followers: 12, SJR: 0.938, h-index: 57)
Art History     Hybrid Journal   (Followers: 218, SJR: 0.153, h-index: 13)
Arthritis & Rheumatology     Hybrid Journal   (Followers: 51, SJR: 1.984, h-index: 20)
Arthritis Care & Research     Hybrid Journal   (Followers: 28, SJR: 2.256, h-index: 114)
Artificial Organs     Hybrid Journal   (Followers: 1, SJR: 0.872, h-index: 60)
ASHE Higher Education Reports     Hybrid Journal   (Followers: 14)
Asia & the Pacific Policy Studies     Open Access   (Followers: 14)
Asia Pacific J. of Human Resources     Hybrid Journal   (Followers: 315, SJR: 0.494, h-index: 19)
Asia Pacific Viewpoint     Hybrid Journal   (SJR: 0.616, h-index: 26)
Asia-Pacific J. of Chemical Engineering     Hybrid Journal   (Followers: 7, SJR: 0.345, h-index: 20)
Asia-pacific J. of Clinical Oncology     Hybrid Journal   (Followers: 6, SJR: 0.554, h-index: 14)
Asia-Pacific J. of Financial Studies     Hybrid Journal   (SJR: 0.241, h-index: 7)
Asia-Pacific Psychiatry     Hybrid Journal   (Followers: 3, SJR: 0.377, h-index: 7)
Asian Economic J.     Hybrid Journal   (Followers: 8, SJR: 0.234, h-index: 21)
Asian Economic Policy Review     Hybrid Journal   (Followers: 4, SJR: 0.196, h-index: 12)
Asian J. of Control     Hybrid Journal   (SJR: 0.862, h-index: 34)
Asian J. of Endoscopic Surgery     Hybrid Journal   (SJR: 0.394, h-index: 7)
Asian J. of Organic Chemistry     Hybrid Journal   (Followers: 4, SJR: 1.443, h-index: 19)
Asian J. of Social Psychology     Hybrid Journal   (Followers: 5, SJR: 0.665, h-index: 37)
Asian Politics and Policy     Hybrid Journal   (Followers: 13, SJR: 0.207, h-index: 7)
Asian Social Work and Policy Review     Hybrid Journal   (Followers: 5, SJR: 0.318, h-index: 5)
Asian-pacific Economic Literature     Hybrid Journal   (Followers: 5, SJR: 0.168, h-index: 15)
Assessment Update     Hybrid Journal   (Followers: 4)
Astronomische Nachrichten     Hybrid Journal   (Followers: 2, SJR: 0.701, h-index: 40)
Atmospheric Science Letters     Open Access   (Followers: 29, SJR: 1.332, h-index: 27)
Austral Ecology     Hybrid Journal   (Followers: 12, SJR: 1.095, h-index: 66)
Austral Entomology     Hybrid Journal   (Followers: 10, SJR: 0.524, h-index: 28)
Australasian J. of Dermatology     Hybrid Journal   (Followers: 8, SJR: 0.714, h-index: 40)
Australasian J. On Ageing     Hybrid Journal   (Followers: 7, SJR: 0.39, h-index: 22)
Australian & New Zealand J. of Statistics     Hybrid Journal   (Followers: 13, SJR: 0.275, h-index: 28)
Australian Accounting Review     Hybrid Journal   (Followers: 4, SJR: 0.709, h-index: 14)
Australian and New Zealand J. of Family Therapy (ANZJFT)     Hybrid Journal   (Followers: 3, SJR: 0.382, h-index: 12)
Australian and New Zealand J. of Obstetrics and Gynaecology     Hybrid Journal   (Followers: 43, SJR: 0.814, h-index: 49)
Australian and New Zealand J. of Public Health     Hybrid Journal   (Followers: 11, SJR: 0.82, h-index: 62)
Australian Dental J.     Hybrid Journal   (Followers: 6, SJR: 0.482, h-index: 46)
Australian Economic History Review     Hybrid Journal   (Followers: 4, SJR: 0.171, h-index: 12)
Australian Economic Papers     Hybrid Journal   (Followers: 23, SJR: 0.23, h-index: 9)
Australian Economic Review     Hybrid Journal   (Followers: 6, SJR: 0.357, h-index: 21)
Australian Endodontic J.     Hybrid Journal   (Followers: 3, SJR: 0.513, h-index: 24)
Australian J. of Agricultural and Resource Economics     Hybrid Journal   (Followers: 3, SJR: 0.765, h-index: 36)
Australian J. of Grape and Wine Research     Hybrid Journal   (Followers: 5, SJR: 0.879, h-index: 56)
Australian J. of Politics & History     Hybrid Journal   (Followers: 13, SJR: 0.203, h-index: 14)
Australian J. of Psychology     Hybrid Journal   (Followers: 18, SJR: 0.384, h-index: 30)
Australian J. of Public Administration     Hybrid Journal   (Followers: 392, SJR: 0.418, h-index: 29)
Australian J. of Rural Health     Hybrid Journal   (Followers: 4, SJR: 0.43, h-index: 34)
Australian Occupational Therapy J.     Hybrid Journal   (Followers: 66, SJR: 0.59, h-index: 29)
Australian Psychologist     Hybrid Journal   (Followers: 11, SJR: 0.331, h-index: 31)
Australian Veterinary J.     Hybrid Journal   (Followers: 19, SJR: 0.459, h-index: 45)
Autism Research     Hybrid Journal   (Followers: 31, SJR: 2.126, h-index: 39)
Autonomic & Autacoid Pharmacology     Hybrid Journal   (SJR: 0.371, h-index: 29)
Banks in Insurance Report     Hybrid Journal   (Followers: 1)
Basic & Clinical Pharmacology & Toxicology     Hybrid Journal   (Followers: 10, SJR: 0.539, h-index: 70)
Basic and Applied Pathology     Open Access   (Followers: 2, SJR: 0.113, h-index: 4)
Basin Research     Hybrid Journal   (Followers: 4, SJR: 1.54, h-index: 60)
Bauphysik     Hybrid Journal   (Followers: 2, SJR: 0.194, h-index: 5)
Bauregelliste A, Bauregelliste B Und Liste C     Hybrid Journal  
Bautechnik     Hybrid Journal   (Followers: 1, SJR: 0.321, h-index: 11)
Behavioral Interventions     Hybrid Journal   (Followers: 9, SJR: 0.297, h-index: 23)
Behavioral Sciences & the Law     Hybrid Journal   (Followers: 23, SJR: 0.736, h-index: 57)
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 9, SJR: 0.11, h-index: 5)
Beton- und Stahlbetonbau     Hybrid Journal   (Followers: 2, SJR: 0.493, h-index: 14)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6, SJR: 0.311, h-index: 26)
Bioelectromagnetics     Hybrid Journal   (Followers: 1, SJR: 0.568, h-index: 64)
Bioengineering & Translational Medicine     Open Access  
BioEssays     Hybrid Journal   (Followers: 10, SJR: 3.104, h-index: 155)
Bioethics     Hybrid Journal   (Followers: 14, SJR: 0.686, h-index: 39)
Biofuels, Bioproducts and Biorefining     Hybrid Journal   (Followers: 1, SJR: 1.725, h-index: 56)
Biological J. of the Linnean Society     Hybrid Journal   (Followers: 15, SJR: 1.172, h-index: 90)
Biological Reviews     Hybrid Journal   (Followers: 3, SJR: 6.469, h-index: 114)
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 42, SJR: 0.12, h-index: 1)
Biology of the Cell     Full-text available via subscription   (Followers: 9, SJR: 1.812, h-index: 69)
Biomedical Chromatography     Hybrid Journal   (Followers: 6, SJR: 0.572, h-index: 49)
Biometrical J.     Hybrid Journal   (Followers: 5, SJR: 0.784, h-index: 44)
Biometrics     Hybrid Journal   (Followers: 37, SJR: 1.906, h-index: 96)
Biopharmaceutics and Drug Disposition     Hybrid Journal   (Followers: 10, SJR: 0.715, h-index: 44)
Biopolymers     Hybrid Journal   (Followers: 18, SJR: 1.199, h-index: 104)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 45, SJR: 0.415, h-index: 55)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 133, SJR: 1.633, h-index: 146)
Biotechnology J.     Hybrid Journal   (Followers: 13, SJR: 1.185, h-index: 51)
Biotechnology Progress     Hybrid Journal   (Followers: 39, SJR: 0.736, h-index: 101)
Biotropica     Hybrid Journal   (Followers: 18, SJR: 1.374, h-index: 71)
Bipolar Disorders     Hybrid Journal   (Followers: 10, SJR: 2.592, h-index: 100)
Birth     Hybrid Journal   (Followers: 34, SJR: 0.763, h-index: 64)
Birth Defects Research Part A : Clinical and Molecular Teratology     Hybrid Journal   (Followers: 2, SJR: 0.727, h-index: 77)
Birth Defects Research Part B: Developmental and Reproductive Toxicology     Hybrid Journal   (Followers: 5, SJR: 0.468, h-index: 47)
Birth Defects Research Part C : Embryo Today : Reviews     Hybrid Journal   (SJR: 1.513, h-index: 55)
BJOG : An Intl. J. of Obstetrics and Gynaecology     Partially Free   (Followers: 219, SJR: 2.083, h-index: 125)

        1 2 3 4 5 6 7 8 | Last   [Sort by number of followers]   [Restore default list]

Journal Cover Advanced Engineering Materials
  [SJR: 0.81]   [H-I: 81]   [26 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1438-1656 - ISSN (Online) 1527-2648
   Published by John Wiley and Sons Homepage  [1576 journals]
  • Texture, Microstructure, and Surface Mechanical Properties of AZ31
           Magnesium Alloys Processed by ECASD
    • Authors: Emigdio Mendoza Fandiño; Raúl E. Bolmaro, Pablo Risso, Vanina Tartalini, Patricia Fernández Morales, Martina Ávalos
      Abstract: The current work presents the results on Mg AZ31B alloy sheets subject to four passes using Equal Channel Angular Sheet Drawing (ECASD) at various temperatures (25, 100, and 200 °C). Textures are determined by laboratory X-ray diffraction and EBSD. EBSD allows the evaluation of the evolution of crystal sizes in function of the distance to the surface and the presence of twinning. Twinning is evident by the analysis of the textures, which show mainly two components, one due to the spin induced by the shearing of ECASD and the other one as a direct product of twinning. Micro-hardness, by Knoop tests on the lateral face of the sheets, are performed, allowing the determination of the influence of SPD on the hardness from surface to surface, going through the center of the sheet. Almost 50% increase on hardening, with respect to the non-processed material, is obtained near to the surface after four and six passes. The effectiveness as a hardening technique declined after the first four passes.The textures of Mg AZ31B alloy sheets subject to Equal Channel Angular Sheet Drawing (ECASD) at various temperatures are measured by X-ray diffraction and EBSD. Figure shows twinning behavior (White lines) of the internal region of the sample subject to ECASD with 120o die at 100 oC.
      PubDate: 2017-07-24T07:40:55.018843-05:
      DOI: 10.1002/adem.201700228
       
  • Tailored Surface Properties of Ceramic Foams for Liquid Multiphase
           Reactions
    • Authors: Katja Schelm; Michael Schwidder, Janis Samuel, Franziska Scheffler, Michael Scheffler
      Abstract: Open cellular ceramic foams are prepared using the replica method. In a second step, these foams are coated with a pre-ceramic or polymer-derived ceramic coating, respectively. Polymer-to-ceramic transformation is studied by SEM with respect to the microstructure, functional groups are characterized by Raman microscopy, density and porosity are determined by pycnometer measurements as well as the surface free energy by means of contact angle measurements. By pyrolysis at different temperatures between 403 and 1273 K, the surface wettability is adjusted in a wide range from hydrophilic to hydrophobic due to the release of organic groups from the pre-ceramic polymers in terms of polymer-to-ceramic transformation. Coated foams are tested in a new potential application: as reactor internals to increase the liquid–liquid interface area in a homogeneously catalyzed multiphase system. As model reaction, a reactive extraction of an organic dye was used and the influence of the surface energy of the foam on the phase dispersion/reaction rate is discussed. The coated foams are able to increase the reaction rate to an extent depending on the surface wettability.Ceramic foams are prepared and coated with pre-ceramic polymers. These coating offers to tailor the surface properties like the wetting behavior in wide range by variation of the pyrolysis temperature. Due to the foams structure, they are useful for novel multi-phase mixing processes. This work shows the dependence of the phase dispersion of two immiscible liquid phases. This work shows the dependence of the phase dispersion of two immiscible liquid phases on the surface wettability of the foams.
      PubDate: 2017-07-21T06:45:28.600191-05:
      DOI: 10.1002/adem.201700418
       
  • Masthead: Adv. Eng. Mater. 7∕2017
    • PubDate: 2017-07-20T04:17:15.99274-05:0
      DOI: 10.1002/adem.201770023
       
  • Contents: Adv. Eng. Mater. 7∕2017
    • PubDate: 2017-07-20T04:17:11.97006-05:0
      DOI: 10.1002/adem.201770024
       
  • Front Cover: Advanced Engineering Materials 7∕2017
    • Abstract: The dynamic nucleation and evolution of α phase during hot deformation is totally different from heat treatment, as discussed in article number 1600859 by Jiangkun Fan and co-workers. The “necklace” microstructure forms and the Burgers orientation relationship between α/β is destroyed. The dynamic βα phase transformation and the dynamic recovery/recrystallization of β phase proceed simultaneously during the hot deformation. There is a competition mechanism between these two processes.
      PubDate: 2017-07-20T04:17:11.547426-05:
      DOI: 10.1002/adem.201770022
       
  • Direct Liquid Injection − Low Pressure Chemical Vapor Deposition of
           Silica Thin Films from Di-t-butoxydiacetoxysilane
    • Authors: Mattias Vervaele; Bert De Roo, Jolien Debehets, Marilyne Sousa, Luman Zhang, Bart Van Bilzen, Stephanie Seré, Herve Guillon, Markku Rajala, Jin Won Seo, Jean-Pierre Locquet
      Abstract: In this work, an unusual silicon chemical vapor deposition precursor is used, which allows the safe deposition of thin silica films in a controlled and reproducible manner at a lower thermal budget with a newly developed direct liquid injection − low pressure chemical vapor deposition system. The deposition is controlled by parameters such as deposition temperature, partial pressure of the gases, and flow rate of the precursor solution. X-ray reflectivity and spectroscopic ellipsometry of the deposited samples show that the thickness of the layers is well controlled by deposition temperature, time, and oxygen flow. A growth rate of 4.5 Å min−1 is obtained without the addition of oxygen, which can be increased to 10.2 Å min−1 by the addition of oxygen. Atomic force microscopy, Rutherford backscattering spectroscopy, Fourier transform infrared spectroscopy, and drop shape analysis are used to measure roughness, composition, and hydrophobicity. Thin films of silicon dioxide are successfully grown. In addition, this newly developed system can be used for a wide range of films by varying the precursors or by co-injecting nanoparticles suspension mixed with the chemical vapor deposition precursor in the direct liquid injection vaporizer.This work describes the use of the unusual silicon chemical vapor deposition precursor di-t-butoxydiacetoxysilane (DADBS), which allows the safe deposition of thin silica films in a controlled and reproducible manner at a lower thermal budget with a newly developed direct liquid injection – low pressure chemical vapor deposition system.
      PubDate: 2017-07-17T04:11:31.246894-05:
      DOI: 10.1002/adem.201700425
       
  • Severe Plastic Deformation by Equal Channel Angular Pressing and Rolling:
           The Influence of the Deformation Path on Strain Distribution
    • Authors: Andrea M. Kliauga; Vitor L. Sordi, Natalia S. De Vincentis, Raúl E. Bolmaro, Norbert Schell, Heinz-Günter Brokmeier
      Abstract: The present work compares two deformation techniques, rolling and Equal Channel Angular pressing (ECAP), and the response offered by three different materials that differ in Stacking Fault Energy (SFE): AA1010 Al, commercially pure Cu, and an austenitic stainless steel. The objective of this investigation is to study the effect of each deformation mode on tensile behavior, deformation mechanism, texture, and microstructure and to establish the influence of the stacking fault energy on said effects. The results show that the different strain paths of ECAP and rolling do not affect the strength, but rolling leads to an accentuated texture and thus to elastic and plastic anisotropy. This finding has practical relevance for micro manufacturing techniques. Furthermore, it is observed that lower SFE results in smaller domain size and higher dislocation density, which are microstructural details related to strength and to the work hardening capacity. Finally, both techniques are able to produce a high amount of high angle grain boundaries, a feature that characterizes refined microstructures. These processes operate at different strain rates; thus, in low SFE materials, a more effective grain fragmentation by deformation-induced twins is observed after the ECAP process.Rolling and equal channel angular pressing (ECAP), and the response offered by three materials were compared. The different strain paths of ECAP and rolling do not affect the strength, but rolling leads to smaller domain sizes and an accentuated texture, which induces elastic and plastic anisotropy. These processes operate at different strain rates; thus, in low stacking fault energy (SFE) materials, a more effective grain fragmentation by deformation- induced twins is observed after the ECAP process.
      PubDate: 2017-07-14T00:34:41.114924-05:
      DOI: 10.1002/adem.201700055
       
  • Preparation of Ni-Encapsulated ZTA Particles as Precursors to Reinforce
           Iron-Based Composites
    • Authors: Juanjian Ru; Yehua Jiang, Rong Zhou, Jing Feng, Yixin Hua, Qionglian Yang
      Abstract: Ni-encapsulated ZTA (ZTA@Ni) particles as precursors to reinforce high chromium cast iron (HCCI) matrix composites are synthesized by electroless deposition using a choline chloride-ethylene glycol (ChCl-EG) ionic liquid additive. The effects of NiSO4 concentration, ChCl-EG concentration, reaction temperature, and ZTA loading capacity on the surface morphology, coating thickness, and elemental distribution of the ZTA@Ni particles are investigated. The deposition sequence of the Ni coating layer is analyzed according to changes in the morphology of samples obtained at different reaction stages. A schematic illustration of the deposition process with the ChCl-EG additive is established. It is demonstrated that ChCl-EG plays the important role of hindering the fast nucleation and crystal growth of Ni nuclei. In addition, the abrasive wear resistance of the ZTA@Ni-reinforced HCCI composite is higher than that of the matrix and the ZTA-reinforced composite. Close contact between the ZTA@Ni particles and the matrix benefits load transfer from the matrix to the reinforcement. The diffusion of metallic Ni leads to the formation of numerous nuclei to refine the particle size of carbides adjacent to the interface and reinforce the interfacial bonding strength.Ni-encapsulated ZTA particles as precursors to reinforce iron matrix composites are prepared by electroless deposition using a choline chloride-ethylene glycol (ChCl-EG) ionic liquid additive. The deposition sequence of the Ni coating layer is analyzed, and a schematic illustration is proposed. ChCl-EG plays the role of hindering the fast nucleation and crystal growth of Ni nuclei.
      PubDate: 2017-07-10T04:16:10.330658-05:
      DOI: 10.1002/adem.201700268
       
  • Carbon Coated Alumina Nanofiber Membranes for Selective Ion Transport
    • Authors: Vera S. Solodovnichenko; Denis V. Lebedev, Victoria V. Bykanova, Alexey V. Shiverskiy, Mikhail M. Simunin, Vladimir A. Parfenov, Ilya I. Ryzhkov
      Abstract: The authors propose a novel type of ion-selective membranes, which combine the advantages of ceramic nanofibrous media with good electrical conductivity. The membranes are produced from Nafen alumina nanofibers (diameter around 10 nm) by filtration of nanofiber suspension through a porous support followed by drying and sintering. Electrical conductivity is achieved by depositing a thin carbon layer on the nanofibers by chemical vapor deposition (CVD). Raman and FTIR spectroscopy, X-ray fluorescence analysis, and TEM are used to confirm the carbon structure formation. The deposition of carbon leads to decreasing porosity (from 75 to 62%) and specific surface area (from 146 to 107 m2 g−1) of membranes, while the pore size distribution maximum shifts from 28 to 16 nm. Measurements of membrane potential in an electrochemical cell show that the carbon coated membranes acquire high ionic selectivity (transference numbers 0.94 for anion and 0.06 for cation in aqueous KCl). Fitting the membrane potential data by the Teorell–Meyer–Sievers model shows that the fixed membrane charge increases proportionally with increasing electrolyte concentration. The carbon coated membranes are ideally polarizable for applied voltages from −0.5 to +0.8 V. The potential applications of produced membranes include nano- and ultrafiltration, separation of charged species, and switchable ion-transport selectivity.A novel type of ion-selective membranes based on alumina nanofibers with the diameter of ∼10 nm is proposed. A carbon layer deposited on the nanofibers by the CVD method provides electrical conductivity and ionic selectivity to the membranes. The potential applications of membranes include nano- and ultrafiltration of charged species. The nanofibrous structure with conductive carbon layer is perspective for realizing switchable ion-transport selectivity.
      PubDate: 2017-07-10T01:18:46.422282-05:
      DOI: 10.1002/adem.201700244
       
  • Influence of Cell Size on Mechanical and Piezoelectric Properties of PZT
           and LNKN Ceramic Foams
    • Authors: Franziska Eichhorn; Jonas Biggemann, Simone Kellermann, Akinobu Kawai, Kensuke Kato, Kenichi Kakimoto, Tobias Fey
      Abstract: Piezoceramic foams made of lead zirconate titanate (PZT) and lithium sodium potassium niobate (LNKN-6) containing an open porosity>75 vol% are manufactured with varying cell size from 1369 to 265 μm and accordingly, strut size from 346 to 46 μm by replica method. Pore size distribution and strut thickness are determined by X-ray micro tomography investigations of PZT foams with 10, 30, 45, and 80 pores per inch (ppi). Fracture strengths σb between 0.29 and 1.52 MPa (PZT) and 0.04 and 0.07 MPa (LNKN-6) are determined by compression test and compared to Gibson and Ashby's model of open- and closed-cell foams and in dependence of the cell size. The longitudinal and transversal coupling coefficients d33 and d31 decrease in a range of 38 to 178 pCN−1 or −13 to −100 pCN−1 compare to dense reference material. In dependence of the cell size, the values of the coupling coefficients change about 79–93%. The relative permittivity decreases 93% by decreasing the cell size of the PZT and LNKN-6 foams.Piezoceramic foams of PZT and LNKN-6 (porosity>75 vol%) are manufactured by replica method. Depending on the cell size fracture strengths σb varied between 0.29 and 1.52 MPa (PZT) and 0.04 and 0.07 MPa (LNKN-6), as well the longitudinal and transversal coupling coefficients d33 and d31 decreased in a range of 38 to 178 pCN−1 or −13 to −100 pCN−1.
      PubDate: 2017-07-07T02:16:30.350748-05:
      DOI: 10.1002/adem.201700420
       
  • Tailoring the Microstructure and Mechanical Property of AZ80 Alloys by
           Multiple Twinning and Aging Precipitation
    • Authors: Chunpeng Wang; Renlong Xin, Dongrong Li, Bo Song, Zhe Liu, Qing Liu
      Abstract: AZ80 alloy is a relatively inexpensive age-hardenable Mg alloy. To improve its precipitation strengthening effect, the discontinuous precipitates generally nucleating from grain boundaries should be reduced. In this study, the authors applied strain-path change compression on a wrought AZ80 alloy to generate multiple {10-12} twins and then the pre-deformed alloy is subjected to aging at 180 °C for different period. The effects of the pre-generated twins on precipitation behavior and hence the mechanical properties are investigated. It is found that multiple {10-12} twins are formed in the AZ80 alloy after two paths of compressions along the transverse and rolling directions. Consequently, continuous precipitation is largely promoted during the subsequent aging process. Moreover, the continuous precipitates preferred to form inside the {10-12} twin lamellae. Discontinuous precipitation is almost inhibited during aging at 180 °C for 4–96 h in the sample containing many multiple twins. Compare to the directly peak-aged sample, the pre-twinned and subsequently peak-aged alloys generally exhibit greatly superior mechanical properties. The yield strength, ultimate strength, and elongation for tension along RD are 242 MPa, 476 MPa, and 19.4%, respectively. These excellent properties are attributed to the combined effects of grain refinement, texture weakening, and enhanced precipitate strengthening.Strain-path change compression is applied on a wrought AZ80 alloy to generate multiple {10-12} twins. During the subsequent aging process, continuous precipitation is largely promoted. Compare to the directly peak-aged sample, the pre-twinned and subsequently peak-aged alloys exhibit greatly superior mechanical properties. These excellent properties are attributed to the combined effects of grain refinement, texture weakening, and enhanced precipitate strengthening.
      PubDate: 2017-07-06T06:21:14.149532-05:
      DOI: 10.1002/adem.201700332
       
  • Crystallography of Martensitic Transformation in Epitaxial Ni50Mn30Ga20
           Thin Film
    • Authors: Bo Yang; Tingting Liu, Xiao Wen Hao, Zong Bin Li, Yu Dong Zhang, Gao Wu Qin, Marie-Jeanne Philippe, Claude Esling, Xiang Zhao, Liang Zuo
      Abstract: In the present work, scanning electron microscopy and electron backscatter diffraction technique revealed that the microstructure of epitaxial Ni50Mn30Ga20 thin films are composed of six different orientated NM martensite variant colonies. In each martensite variant colony, there are eight different orientated NM martensite variants. The six NM and 7M martensite variant colonies are transformed from six (101)A planes of austenite, with the transformation consequence from Austenite to 7M martensite and then to NM martensite. Cross section TEM examination reveals the coexistence of 7M martensite and NM martensite. The habit plane between 7M martensite and NM martensite can be determined as (001)mono of 7M martensite and (112)Tetr of NM martensite.EBSD characterization and crystallographic calculation indicates that the martensitic transformation sequence is from Austenite to 7M martensite and then to NM martensite (A  7M  NM) in the Ni50Mn30Ga20 thin films. Cross section TEM images presents the coexistence of 7M and NM martensite and the habit plane between the 7M and NM martensite.
      PubDate: 2017-07-06T06:20:54.167751-05:
      DOI: 10.1002/adem.201700171
       
  • Enhanced Bipolar Strain Response in Lithium/Niobium Co-Doped
           Sodium–Barium Bismuth Titanate Lead-Free Ceramics
    • Authors: Shang Gao; Zhaojun Yao, Li Ning, Guangzhi Dong, Huiqing Fan, Qiang Li
      Abstract: The (Na0.484Bi0.456Ba0.06)Ti0.97Nb0.03O3 − xLi+ (x = 0, 0.005, 0.01, 0.015) lead-free piezoelectric ceramics are prepared by conventional solid-state reaction technique. X-ray diffraction and surface scanning electron microscope images confirm the pure perovskite structure of sintered ceramics. Electric field and composition-dependent strain behavior are investigated. The highest bipolar strain of 0.47% is achieved at x = 0.01 with the applied electric-field of 70 kV cm−1, and the corresponding normalized strain (d33*) reaches up to 671 pm V−1. Moreover, the giant strain exhibits excellent thermal stability and fatigue-resistance (within 105 switching cycles) properties. The origin of the strain can be attributed to transition between ferroelectric and relaxor ferroelectric induced by the applied electric field, and introduction of Li cations further enhances the strain behavior. AC impedance analysis indicate the appearance of grain boundary effect with increasing Li+ addition, which is also reflected on the dielectric and dielectric loss curves. It is believed that the environmental friendly binary system can be a promising candidate for piezoactuators.In this work, Li/Nb co-doped Na0.484Bi0.456Ba0.06TiO3 ceramics are prepared using conventional solid-state reaction method. The giant electric-field-induced strain of 0.47% (E = 70 kV cm–1) is achieved, meanwhile, the strain exhibits excellent fatigue resistance and temperature stability properties. The Li/Nb modified lead-free polycrystalline ceramics can be a promising candidate for actuator applications.
      PubDate: 2017-07-06T06:20:28.580674-05:
      DOI: 10.1002/adem.201700125
       
  • Mass Transfer Performance of Porous Nickel Manufactured by Lost Carbonate
           Sintering Process
    • Authors: Pengcheng Zhu; Yuyuan Zhao
      Abstract: Open cell porous metals are excellent electrode materials due to their unique electrochemical properties. However, very little research has been conducted to date on the mass transport of porous metals manufactured by the space holder methods, which have distinctive porous structures. This paper measures the mass transfer coefficient of porous nickel manufactured by the Lost Carbonate Sintering process. For porous nickel samples with a porosity of 0.55–0.75 and a pore size of 250–1500 μm measured at an electrolyte flow velocity of 1–12 cm s−1, the mass transfer coefficient is in the range of 0.0007–0.014 cm s−1, which is up to seven times higher than that of a solid nickel plate electrode. The mass transfer coefficient increases with pore size but decreases with porosity. The porous nickel has Sherwood numbers considerably higher than the other nickel electrodes reported in the literature, due to its high real surface area and its tortuous porous structure, which promotes turbulent flow.Porous nickel manufactured by the Lost Carbonate Sintering (LCS) process has higher Sherwood numbers than many other nickel electrodes in the modest range of Reynolds number due to its high real surface area and tortuous structures.
      PubDate: 2017-07-05T04:31:56.334266-05:
      DOI: 10.1002/adem.201700392
       
  • Comparative Phenomenological Study of Fracture Behavior of Ceramic and
           Glass Foams under Compressive Stress Using In Situ X-Ray Microtomography
    • Authors: Jana Hubálková; Claudia Voigt, Anne Schmidt, Kirsten Moritz, Christos G. Aneziris
      Abstract: This contribution is dealing with the phenomenological characterization of the cracking and damage of two different brittle foam materials (ceramic foams and glass foams) under compressive load. The compression tests were performed in situ in X-ray microtomograph in order to visualize the formation of single crack and crack patterns in 3D. Successive microtomographic scans at different levels of compression strain provide an insight into the stressed microstructure of the ceramic and glass foams. The linked evaluation of the microtomographic scans and registered load-displacement curves clarify the different mechanical response of ceramic and glass foams. Both, ceramic and glass foams show in the early stages of load nearly elastic response. The compressive loading above the elastic region induces different behavior. Ceramic foams response with local failure of single struts and edges to increasing loading. In case of glass foams, the response is depending on whether the cells are predominantly open or close. Predominantly open cell glass foams features very brittle behavior whereas close cell glass foams show pseudo-ductile behavior with a formation of a crushing band transversal to the loading direction.This study is concerned with the phenomenological characterization of damage of two different brittle foam materials (ceramic and glass foams) under compressive load performed in situ in X-ray microtomograph. The linked evaluation of the microtomographic scans at different levels of compression strain and stress–strain curves clarify the different mechanical response of ceramic and glass foams. While the ceramic foams are subject of successive damage process, the response of glass foams is depending on whether the cells are open or close. Predominantly open cell glass foams features very brittle behavior with a shear deformation band whereas close cell glass foams show pseudo-ductile behavior involving the formation of a compaction deformation band perpendicular to the loading direction.
      PubDate: 2017-07-05T04:31:26.356567-05:
      DOI: 10.1002/adem.201700286
       
  • Simultaneous XEDS-EBSD Study of NiCoAlFeCu(Cr,Ti) Multi-Component Alloys
    • Authors: Francisco Cruz-Gandarilla; Oscar Coreño-Alonso, José Gerardo Cabañas–Moreno, Lisa H. Chan, Cynthia Gómez-Esparza, Roberto Martínez Sánchez
      Abstract: NiCoAlFeCu, NiCoAlFeCuCr, and NiCoAlFeCuCrTi high-entropy alloys are prepared by mechanical alloying and sintered at 1200 °C and a pressure of 1.5 GPa for 3 h. The alloys were characterized by X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and X-ray energy dispersive spectrometry (XEDS). The phases found are mostly variants of the face centered cubic (fcc) phases (space group Fm3¯m), bcc (space group Im3¯m), and hexagonal (space group P63/mmc). Adding Ti to the NiCoAlFeCuCr system has strong effects on the solubility of the elements in the different phases and increases dramatically the number of phases present. The use of EBSD and XEDS allowed identification of a cubic phase in NiCoAlFeCu samples, which cannot be identified by XRD alone, and confirmed its identification by XRD in NiCoAlFeCuCr samples. The spatial distribution of phases and the grain structure in the three different samples, measured by EBSD and XEDS, is reported.Phase analysis in NiCoAlFeCu HEA alloys by XRD is frequently complicated by the simultaneous occurrence of several simple fcc and bcc structures. By linking together EBSD and XEDS analysis, cubic phases with similar lattice parameters are differentiated and their microscopic spatial distribution is revealed.
      PubDate: 2017-07-05T04:31:13.915639-05:
      DOI: 10.1002/adem.201700215
       
  • Surface Functionalization of Micro/Nanostructured Titanium with Bioactive
           Ions to Regulate the Behaviors of Murine Osteoblasts
    • Authors: Guisen Wang; Yi Wan, Bing Ren, Teng Wang, Zhanqiang Liu
      Abstract: Surface topography and chemical composition are centrally important in current implants for enhancing cellular responses. To investigate the synergistic effect of micro/nanostructure and bioactive ions on the spreading, proliferation, and differentiation of murine osteoblasts, the micro/nanostructured titanium surface containing bioactive ions (Zn2+ and Sr2+) was fabricated via sandblasting, acid etching, alkali-heat treatment, and ion exchange. Compared to polished titanium substrates, micro/nanostructured titanium substrates displayed the enhanced roughness and hydrophilicity. And surface functionalization of micro/nanostructured using Zn2+/Sr2+ ions exhibited the sustained release for a period of time. Meanwhile, cell experiments indicated that the Zn/Sr loaded micro/nanostructured titanium surfaces had a great potential to promote cell spreading, proliferation, and differentiation. This study provides a more promising method to design the surface of titanium implants for enhancing osseointegration.The hierarchical micro/nanostructure containing bioactive ions (Zn2+ and Sr2+) were fabricated on the surface of titanium by combined use of sandblasting, acid etching, alkali-heat treatment and ion exchange. The treated titanium substrates presented sustained ion release behavior. Surface functionalization of micro/nanostructured titanium with bioactive ions provided a favorable interfacial environment for the spreading, proliferation, and differentiation of osteoblasts.
      PubDate: 2017-07-03T08:01:11.345968-05:
      DOI: 10.1002/adem.201700299
       
  • Numerical Modeling of Flow Conditions during Steel Filtration Experiments
    • Authors: Amjad Asad; Eric Werzner, Cornelius Demuth, Steffen Dudczig, Anne Schmidt, Subhashis Ray, Christos G. Aneziris, Rüdiger Schwarze
      Abstract: In the present article, the performance and the efficiency of ceramic filters for continuous steel filtration in an induction crucible furnace, which is part of the steel casting simulator facility located at Technische Universität Bergakademie Freiberg, is investigated numerically. In order to achieve this objective, a macro-scale simulation for the melt flow in the crucible is coupled with a pore-scale simulation for the flow inside the ceramic filter that is adequately resolved by its detailed filter geometry, obtained from computed tomography scan images. The considerable influence of the filter on the flow field is indicated from the present results. Moreover, the efficiency of the employed filter is also determined and compared for two pore densities.Numerical simulations are performed in order to determine the filtration efficiency of ceramic filters in an induction crucible furnace. Both pore-scale and macro-scale simulations are coupled in order to achieve this task. The considerable influence of the filter on the flow field is shown in the present article. Moreover, it is indicated that the filtration efficiency of the filters depends on the pore density of the filters.
      PubDate: 2017-07-03T07:07:30.137184-05:
      DOI: 10.1002/adem.201700085
       
  • Composite Materials Based on Shape-Memory Ti2NiCu Alloy for Frontier
           Micro- and Nanomechanical Applications
    • Authors: Peter Lega; Victor Koledov, Andrey Orlov, Dmitry Kuchin, Aleksey Frolov, Vladimir Shavrov, Alexandra Martynova, Artemii Irzhak, Alexander Shelyakov, V. Sampath, Vladimir Khovaylo, Pnina Ari-Gur
      Abstract: Composite materials based on Ti2NiCu alloy, exhibiting shape memory effect (SME), have the unique capability of temperature-controlled reversible actuation on micro- and nanoscale. Three approaches to realizing this objective are demonstrated. The first one involves creating an amorphous-crystalline composite by passing accurately controlled electrical pulses through a rapidly-quenched amorphous Ti2NiCu ribbon. After undergoing partial crystallization (40–60% of crystalline phase), the composite acquires SME, and can be trained to undergo reversible deformations by a single bend in the martensitic condition. The second approach involves a layered composite consisting of a layer of Ti2NiCu and an elastic metallic layer, such as Pt. It is found that the reversible deformation of the Ti2NiCu/Pt composite created by FIB milling is>1%, when the thickness of SME layer is reduced from 1 μm to 100 nm. Further reduction (below 100 nm) results in smaller deformation. The third approach combines these two methods. A layer of crystalline Ti2NiCu is covered by a layer of the same alloy in the amorphous state using FIB. The authors believe that these composites, exhibiting SME, will trigger the fabrication of many novel devices and open up new opportunities in diverse areas of nanoscience and nanotechnology.This manuscript presents three approaches to realizing composite materials based on Ti2NiCu alloy, exhibiting shape memory effect for temperature-controlled reversible actuation on micro- and nanoscale. The authors believe that these composites will open up new opportunities in diverse areas of nanoscience and nanotechnology.
      PubDate: 2017-07-03T01:26:31.954358-05:
      DOI: 10.1002/adem.201700154
       
  • Application of X-Ray Microtomography to Evaluate Complex Microstructure
           and Predict the Lower Bound Fatigue Potential of Cast
           Al–7(0.7)Si–4Cu–3Ni–Mg Alloys
    • Authors: Thomas O. Mbuya; Ian Sinclair, Katherine A. Soady, Philippa A. S. Reed
      Abstract: The 3D architecture of intermetallics and porosity in two multicomponent cast Al–7(0.7)Si–4Cu–3Ni–Mg alloys is characterized using conventional microscopy and X-ray microtomography. The two alloys are found to contain intermetallic phases such as Al3Ni, Al3(NiCu)2, Al9FeNi, and Al5Cu2Mg8Si6 that have complex networked morphology in 3D. The results also show that HIPping does not significantly affect the volume fraction, size, and shape distribution of the intermetallic phases in both alloys. A novel technique similar to serial sectioning that circumvents quantification difficulties associated with interconnected particles is used to quantify the intermetallics. The largest particle size distribution is then correlated to fatigue performance using extreme value analysis to predict the maximum particle size in a sample of S-N fatigue specimens and subsequently, the lower bound fatigue life. The predictions are found to correlate well with fatigue data. The effect of HIPping on porosity characteristics is also characterized. Large pore clusters with complex morphology are observed in the unHIPped versions of both alloys, but more significant in the low Si (Al–0.7Si–4Cu–3Ni–Mg) alloy. However, these are significantly reduced after HIPping. The differences between 2D and 3D pore morphology and size distribution is discussed in terms of the appropriate pore size parameter for fatigue life prediction.Two cast Al–7(0.7)Si–4Cu–3Ni–Mg alloys contain a complex 3D network of intermetallics and large complex-shaped pores. HIPping reduces the volume fraction (Vf), size and shape complexity of pores, but no effect is observed for intermetallics except a slight reduction in the Vf of 0.7 wt% Si alloy. A novel technique akin to serial sectioning is used to quantify intermetallics. The upper tail of particle sizes correlates well with fatigue crack initiating particles.
      PubDate: 2017-07-03T01:26:19.534505-05:
      DOI: 10.1002/adem.201700218
       
  • 3D Printing of Free-Standing Stretchable Electrodes with Tunable Structure
           and Stretchability
    • Authors: Hong Wei; Kai Li, Wen Guang Liu, Hong Meng, Pei Xin Zhang, Chao Yi Yan
      Abstract: Free-standing stretchable electrodes with high stretchability and resistance stability are desired for future wearable electronic applications. However, it is very difficult to achieve high stretchability (typically restricted by the substrate) and meanwhile maintain low resistance change upon stretching. Innovative designs and fabrication strategies need to be developed to meet the required characteristics. We report the successful fabrication of free-standing wavy elastic electrodes achieving very high stretchability (>300% for PDMS) and outstanding resistance stability (only 5% relative resistance change at 100% strain), simultaneously. We systematically studied designs with different joining angles and shapes to optimize the electrode performances. The 3D free-standing electrodes with outstanding stretchability and electrical stability has great potential for further optimizations and applications in future stretchable and wearable electronic devices.We demonstrate the successful 3D printing of wavy elastic electrodes with high stretchability and excellent resistance stability. Stretchable electrodes with different shapes and designs were systematically studied. Serpentine shaped design with 45° joining angle exhibited the best performances, which is in contrary to conventional 2D electrodes. Our fabrication strategy paves the way for further 3D printing of more complex stretchable electronic devices.
      PubDate: 2017-07-03T01:25:27.849675-05:
      DOI: 10.1002/adem.201700341
       
  • Gradient Structures in Thin-Walled Metallic Tubes Produced by Continuous
           High Pressure Tube Shearing Process
    • Authors: Rimma Lapovok; Yuanshen Qi, Hoi P. Ng, Laszlo S. Toth, Yuri Estrin
      Abstract: A new severe plastic deformation process, the authors refer to as High Pressure Tube Shearing (HPTS), is proposed. This type of deformation processing enhances the strength of the walls of metallic tubes by producing gradient microstructures with ultrafine grained layers in near-surface regions. The thickness of the layers associated with a gradient in microstructure can be controlled by tuning the rotational and translational speeds of the process. The paper describes several examples of steel and titanium tubes processed by different variants of HPTS. The possibility of producing gradient microstructures with ultrafine grained layers at inner or outer surface of a tube, or at both surfaces is demonstrated by in-depth theoretical analysis, finite element simulations, and experimental investigation of the microstructure and texture of tube walls.A new continuous severe plastic deformation process, named High Pressure Tube Shearing, is proposed, Figure 1. This deformation technique enhances the strength of the walls of metallic tubes by producing gradient microstructures with ultrafine grained layers in near-surface regions. The thickness of the layers associated with a gradient in microstructure can be controlled by tuning the rotational and translational speeds.
      PubDate: 2017-07-03T01:21:52.402208-05:
      DOI: 10.1002/adem.201700345
       
  • Microstructure Evolution and Ablation Mechanism of C/C and C/C-SiC
           Composites Under a Hypersonic Flowing Propane Torch
    • Authors: Xiaochao Jin; Xueling Fan, Peng Jiang, Qiang Wang
      Abstract: The high-velocity oxygen fuel thermal spray system can provide a hypersonic flowing environment in which the temperature, pressure, and speed are all sufficiently high to represent a more realistic environment of hypersonic vehicles than that produced by traditional oxyacetylene flame. In this work, the ablation resistance of C/C and C/C-SiC composites under hypersonic flowing propane flame is investigated, and the microstructure evolution during the ablation process is examined. It is found that different ablation regions are formed depending on the size, and the distributions of temperature and pressure on the front surface of the samples. With the increase of ablation time, a dense and continuous oxide layer forms, which acts as a barrier to prevent the interaction of oxidizing gases and composites, and can also block the conducted heat and resist high temperature scouring of hypersonic flowing flame. In addition, a numerical analysis is performed using ANSYS Fluent software to investigate the fields of velocity, pressure, and temperature on the front surface and around the carbon fibers of the sample. The simulation results further demonstrate the evolution of microstructures of C/C and C/C-SiC composites.High-velocity oxygen fuel thermal spray system can provide a hypersonic flowing environment in which the temperature, pressure, and speed are all sufficiently high to represent a realistic environment of hypersonic vehicles. In this artical, experimental investigations are performed under hypersonic flowing propane torch to provide a better understanding of the ablation mechanism of ultra-high temperature ceramics modified C/C composites.
      PubDate: 2017-07-03T01:21:05.149151-05:
      DOI: 10.1002/adem.201700239
       
  • Rietveld Texture Analysis for Metals Having Hexagonal Close-Packed Phase
           by Using Time-of-Flight Neutron Diffraction at iMATERIA
    • Authors: Yusuke Onuki; Akinori Hoshikawa, Soichiro Nishino, Shigeo Sato, Toru Ishigaki
      Abstract: Texture is an important property especially for metallic materials having hexagonal close-packed crystal structure. In order to understand the overall property or change in the microstructure of materials, neutron diffraction is a powerful tool of investigation. In this study, we attempt to measure the textures of Ti­–6Al–­4V (mass%) alloy by using a time-of-flight neutron diffractometer, iMATERIA. The results indicate that the texture measurement for the hexagonal phase is possible with the same method as for cubic metals. The texture of cubic β phase, whose volume fraction is several percent, can simultaneously be determined together with the hexagonal α phase.Quantitative texture measurement/analysis for a HCP crystal is verified by using data from iMATERIA, time-of-flight-neutron diffractometer at J-PARC MLF, Japan. In the current study, textures of both HCP α and BCC β phases in Ti-6 mass% Al-4 mass% V are simultaneously determined by the Rietveld texture analysis using data acquired at a single neutron exposure.
      PubDate: 2017-07-03T01:20:47.925262-05:
      DOI: 10.1002/adem.201700227
       
  • Open-Porous Silicon Nitride-Based Ceramics in Tubular Geometry Obtained by
           Slip-Casting and Gelcasting
    • Authors: Dominik Brouczek; Thomas Konegger
      Abstract: Owing to its unique properties, silicon nitride is a frequently used materials choice in highly demanding applications in terms of thermal and mechanical load. In this work, porous silicon nitride-based support materials in hollow-tube configuration are generated through colloidal forming, and their respective properties for potential applications in the fields of membrane-based separation, filtration, or catalysis are evaluated. Shaping of the ceramics is achieved by two distinct casting techniques, slip-casting, and gelcasting, and the results of the respective methods are set in relation. Furthermore, a special focus is set on the correlation between sintering parameters and resulting porosity. Subsequently, air permeabilities of the generated structures are determined, illustrating a direct relation between processing parameters and resulting permeability. Darcian permeability values of up to 9 · 10−16 m2 are observed for samples exhibiting total porosities between 32 and 41 %. The findings allow for a predictability of suitable permeation properties for the structures’ anticipated application as complex-shaped non-oxide ceramic supports for membrane-based separation or catalysis, or as high-performance filter materials.Two distinct colloidal-based casting approaches (slip-casting and gelcasting) are evaluated for the generation of porous Si3N4 ceramics in tubular geometry, suitable for prospective applications in the fields of separation or catalysis. Partial sintering facilitates tightly controllable pore morphologies, thus allowing for a direct correlation between processing, porosity, and permeability characteristics of the tubular structures prepared.
      PubDate: 2017-07-03T01:20:37.057617-05:
      DOI: 10.1002/adem.201700434
       
  • A New Horizon for Barreling Compression Test: Exponential Profile Modeling
    • Authors: Mehdi Fardi; Ralph Abraham, Peter D Hodgson, Shahin Khoddam
      Abstract: Exponential Profile Model (EPM) has been recently proposed to interpret barreling compression test's (BCT) data. A basic solution of EPM enables estimation of friction factor and to calculate distributions of strain rate (and strain) in the sample. These critical pre-requisites allow to identify material's flow behavior and to indirectly measure static, dynamic, and meta-dynamic recrystallization properties of the material based on the behavior. In this work, EPM's basic solution is employed in a fixed friction factor mode, the model is assessed and its potentials are outlined. The assessment includes comparing EPM's sample solutions with two reference solutions. The references are a non-isothermal finite element model of BCT and the commonly used solution of the test; Cylindrical Profile Model (CPM). It is shown that despite variations of strain, strain rate, and temperature in Al1050 and AISI 304 stainless steel BCT samples, EPM's solutions agree reasonably well with the finite element solutions. This is particularly true for effective strains bellow 0.7 and friction factors bellow 0.2. It is concluded that EPM presented a far more reliable solution than CPM.A new analytical model for barreling compression test (Top) is introduced. The model (EPM), proves to be far more reliable than the existing models such as Cylindrical Profile Model. EPM relies on the initial and deformed geometry of the test sample (Top) and a new velocity filed (bottom) to identify the test's friction factor and its strain distribution.
      PubDate: 2017-06-29T07:26:25.153451-05:
      DOI: 10.1002/adem.201700328
       
  • Highly Conductive Three-Dimensional Printing With Low-Melting Metal Alloy
           Filament
    • Authors: Kimball Andersen; Yue Dong, Woo Soo Kim
      Abstract: It has been challenging to develop a new functional material with high conductivity for the Fused Filament Fabrication (FFF) based 3D printing technology. The proposed low-melting metal alloy filament provides the key to overcome the challenges including printability and conductivity. For this report, two metal alloys are designed to evaluate their suitability for FFF. In order to achieve material compatibility of the designed filament material with the nozzle materials, different nozzle materials are also investigated using thermal analysis. Then, a custom extrusion nozzle is suggested using thermal modeling to optimize the melt-zone for reliable extrusion. And finally, 3D printed circuit is demonstrated from a 3D printed plastic case to the integrated printed-alloy connections for the light-emitting device.Highly conductive metal 3D printing is demonstrated with low-melting Tin-Bismuth-Silver alloy filaments for the integration of 3D printed electronics. The developed alloy filament demonstrates good extrusion characteristics due to its thixotropic nature. Co-deposition of the alloy into 3D printed PLA structures shows compatible with existing thermoplastic additive manufacturing systems.
      PubDate: 2017-06-28T08:05:56.978033-05:
      DOI: 10.1002/adem.201700301
       
  • Synthesis and Vacuum Cold Spray Deposition of Biofunctionalized
           Nanodiamond/Hydroxyapatite Nanocomposite for Biomedical Applications
    • Authors: Deyan Li; Xiuyong Chen, Yongfeng Gong, Botao Zhang, Yi Liu, Peipeng Jin, Hua Li
      Abstract: Insufficient biological performances of titanium alloys have been the long-standing problems for their clinical applications. Here, we report synthesis of novel hydroxyapatite/nanodiamond-bone morphogenetic protein 2 (HA-ND/BMP2) composite powder and their coatings deposited by vacuum cold spray operated at room temperature. The microstructure and chemistry of the HA-ND/BMP2 powder and coatings are characterized by transmission electron microscopy, field-emission scanning electron microscopy, thin-film X-ray diffraction, Raman spectrometry, and X-ray photoelectron spectroscopy. In vitro growth assay of osteoblasts on the coatings showed that the biofunctionalized nanodiamonds promoted cell adhesion and proliferation. This study provides a promising technical route for constructing biofunctionalized nanocomposites coatings for potential biomedical applications.Novel hydroxyapatite/nanodiamond-bone morphogenetic protein 2 (HA-ND/BMP2) coatings are fabricated on titanium substrates for biomedical applications by VCS processed at room temperature. The nanocomposite coatings offer significantly promoted biological properties for the titanium substrates by the presence of NDs and BMP2.
      PubDate: 2017-06-28T08:05:42.049826-05:
      DOI: 10.1002/adem.201700363
       
  • Phase-Control Enabled Superior Mechanical and Electrical Properties of
           Nanocrystalline Tungsten-Molybdenum Thin Films
    • Authors: G. Martinez; C. V. Ramana
      Abstract: The authors report on the design and stabilization of the mechanically hard and electrically resistive β-phase W-Mo nanocrystalline thin films at room-temperature (RT). The W-Mo films are deposited under different deposition temperatures in the range of Ts = RT–30 °C. Structural analyses indicate that, as deposited at RT, the W-Mo films crystallize in the metastable β-phase, while those deposited at higher Ts (100–300 °C) exhibit the thermodynamically stable α-phase. The phase-effect is significant on the mechanical characteristics; superior hardness (H); and modulus of elasticity (Er) are found in β-than in α-phase W-Mo films. At the β-to-α phase transformation, significant reduction occurs in H (40  25 GPa) and Er (275  225 GPa) coupled with a reduction in electrical-resistivity (320  180 µΩ-cm). Their findings and the phase-mechanical-electrical property correlation established may provide further possibilities to design and tailor the performance of W-based thin films for future electronic and electromechanical device applications.The authors report on the superior mechanical properties of nanocrystalline W-Mo thin films. The phase-effect is significant on the hardness and elastic modulus, which are high in β-than in α-phase W-Mo films. These findings and the phase-mechanical-electrical property correlation established may provide further possibilities to design and tailor the performance of W-based films for future electronic and electromechanical device applications.
      PubDate: 2017-06-28T08:05:29.719304-05:
      DOI: 10.1002/adem.201700354
       
  • Ceramic Fibers Reinforced Functionally Graded Thermal Barrier Coatings
    • Authors: Chang Wang; Xiufang Cui, Guo Jin, Zonghong Gao, Jiannong Jin, Zhaobing Cai, Yongchao Fang
      Abstract: The long-term durability is a considerable challenge for the use of thermal barrier coatings (TBCs). In order to solve this problem, introduction of yttria-stabilized zirconia (YSZ) short fibers in functionally graded system is employed to strengthen the durability of TBCs. Four coatings are deposited on In738LC substrate by atmospheric plasma spray (APS). Thermal cycling behaviors and fiber toughening mechanisms of coatings are systematically studied. Result shows that the thermal cycling lifetime of graded TBCs with the addition of fibers can reach 406 ± 21 at 850 °C, which increases by 60% compared to that of typical APS YSZ TBCs. Moreover, the improvement of lifetime mainly attributes to the fiber breakage, the fiber-matrix interface debonding, and the crack deflection.In this study, a novel method, namely, introduction of yttria-stabilized zirconia (YSZ) short fibers in functionally graded system, is used to solve the long-term durability of TBCs. Thermal cycling lifetime of this TBC is improved greatly. The improvement is mainly attributed to the fiber breakage, the fiber-matrix interface debonding, and the crack deflection.
      PubDate: 2017-06-23T03:32:30.183391-05:
      DOI: 10.1002/adem.201700149
       
  • Hot Rectangular Extrusion Textures of Six Mg-Alloys Via Neutron
           Diffraction
    • Authors: Heinz-Günter Brokmeier
      Abstract: Due to the high quality and statistics utilizing neutron diffraction for texture analyses, the crystallographic texture variation of six Mg-alloys is described in detail (AM20–AZ31–AZ61–AZ91–ZC71–WE43). More or less in all cases, the crystallographic texture is composed of some ideal texture components such as {0001} and {10–10} and fiber components such as  // ND and  // ED. There is a dependency of the existence and texture sharpness of texture components with alloying elements such as the amount of Al. ZC71 is special with one dominating texture component {10–10} . WE43 shows the split of the central pole in the basal pole figure but texture components are identical to other alloys without the tilt.Crystallographic texture of rectangular hot extruded Mg-alloys show a strong variation in texture type and texture sharpness. Examples show the (0002) and the (10–10) pole figures of Mg-AZ61 and MG-ZC71, first one with strong deformation texture and second one with strong recrystallization texture.
      PubDate: 2017-06-19T02:21:02.739758-05:
      DOI: 10.1002/adem.201700234
       
  • Improving Mechanical Properties of cp Titanium by Heat Treatment
           Optimization
    • Authors: Francis Wagner; Abdelouahab Ouarem, Thiebaud Richeton, Laszlo S. Toth
      Abstract: The yield stress and the ductility are very important mechanical quantities for materials selection. The paper deals with the question: how far is it possible to increase the yield stress without a significant loss of ductility by optimizing the final heat treatment in the elaboration stage. Commercially pure titanium sheets are subjected to different thermo-mechanical treatments to produce seven metallurgical states. The textures and the microstructures of the samples are studied by Electron Back Scattering Diffraction measurements, the mechanical behavior by tensile testing along the previous rolling, and the transverse directions of the sheet. The obtained microstructures display different grain sizes and varying fractions of recrystallized grains, together with slightly dissimilar textures. The yield stress increases with the decreasing grain size and obeys the classical Hall–Petch law. The grain size reduction results in a small decrease of ductility for extension along the rolling direction when the recrystallized volume fraction is higher than 80%. For extension along the transverse direction, however, the homogeneous deformation strongly decreases as soon as the material contains a small fraction of non-recrystallized grains. A good compromise between high yield stress and ductility is identified in a metallurgical state close to the end of primary recrystallization. This material state insures a relatively small grain size with all grains being in a recrystallized state.Mechanical properties are determined for cp titanium sheets after various heat treatments leading to different states (full or partial recrystallyzation). The YS increases without significant loss of ductility due to grain size and texture. Anisotropy is taken into account to define the best compromise.
      PubDate: 2017-06-19T02:20:42.877674-05:
      DOI: 10.1002/adem.201700237
       
  • Life-Cycle Assessment of Solar Charger with Integrated Organic
           Photovoltaics
    • Authors: Gisele A. dos Reis Benatto; Nieves Espinosa, Frederik C. Krebs
      Abstract: Organic photovoltaics (OPV) applied in a commercial product comprising a solar charged power bank is subjected to a life cycle assessment (LCA) study. Regular power banks harvest electricity from the grid only. The solar power bank (called HeLi-on) is however, a power bank that includes a portable OPV panel, enabling the possibility to be charged from the sun, and not only from the grid. In this paper, two well-established power bank products using amorphous silicon solar panels (a-Si PV) and a regular power bank without any portable solar panel is compared to HeLi-on. The environmental impact of the products is quantified with the aim of indicate where eco-design improvements would make a difference and to point out performance of a portable solar panel depending on the context of use (Denmark and China), realistic disposal scenarios and the recycling relevance particularly concerning metals content.Ecodesign of electronic equipment as a key action supporting circular economy, reduce the energy consumption and other environmental impacts occurring throughout their life cycle. In this study, a new organic photovoltaic-based solar charger produced according to circular economy principles, is compared to well-established products in terms of environmental performance when used and disposed in Denmark or China, indicating ecodesign improvements.
      PubDate: 2017-06-16T07:56:03.278672-05:
      DOI: 10.1002/adem.201700124
       
  • Large-Scale Synthesis of Nanostructured Nitride Layer on Ti Plate Using
           Mechanical Shot Peening and Low-Temperature Nitriding
    • Authors: Quantong Yao; Jian Sun, Depeng Shen, Weiping Tong, Liang Zuo
      Abstract: A nanostructured nitride layer is produced on a large titanium plate using mechanical shot peening (MSP) followed by a low-temperature gaseous nitriding method. The combined effect of the MSP and low-temperature nitriding on the microstructural evolution and mechanical properties is investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, as well as hardness, wear resistance, and toughness tests. The results of the characterization are compared to a coarse-grained specimen produced by a standard nitriding process. The results show that a nitride layer with a thickness of 10–15 µm is produced on the MSP-treated Ti plate after nitriding at 550 °C for 5 h. The nitride layer is composed of nanostructured ϵ-TiN and γ-Ti2N phases with a high supersaturation of nitrogen. The nitriding kinetics is significantly enhanced by the nanocrystalline structure. The surface hardness, thickness of the hardened layer, and wear resistance of the nitrided MSP Ti plate are all enhanced relative to the coarse-grained nitrided sample. The toughness of the nanostructured nitrides is greatly improved compared with the conventional nitrided specimen.The authors firstly realize surface nanocrystallization technology in industrialization application. The gaseous nitriding can be performed on Ti plate at low nitriding temperature of 550 °C by nanocrystalline layer assistance. The nitrided layer thickness and toughness are significantly improved comparing with that of the coarse-grained nitrided specimen.
      PubDate: 2017-06-16T07:55:55.708924-05:
      DOI: 10.1002/adem.201700157
       
  • In Situ Study of Deformation Twinning and Detwinning in Helium Irradiated
           Small-Volume Copper
    • Authors: Wei-Zhong Han; Ming-Shuai Ding, R. Lakshmi Narayan, Zhi-Wei Shan
      Abstract: The influence of nanoscale helium bubbles on the deformation twinning and detwinning behavior of submicron-sized Cu is investigated under tension, compression, and cyclic loading. In situ nanomechanical tests performed inside a transmission electron microscope reveal that twinning and detwinning occur readily in helium irradiated copper under both tension and compression. Continuous shearing of helium bubbles by Shockley partials leads to twin formation, whereas the residual back-stress accumulated from dislocation-bubble interactions assist in detwinning. These interactions also elevate the critical shear stress for partial dislocation slip in helium irradiated Cu compared to that in fully dense Cu. The growth twin boundaries can significantly enhance the twinning stress in helium irradiated Cu pillar, and deformation twin-growth twin boundary interaction promotes the formation of internal crack and thus accelerates failure. The effect of crystallographic orientation and sample size on the overall deformation characteristics of helium irradiated Cu is briefly discussed. The current studies show that deformation twinning and detwinning are also active deformation models in helium irradiated small-volume copper.In situ nanomechanical tests performed inside a transmission electron microscope reveal that twinning and detwinning occur readily in helium irradiated copper under both tension and compression. Continuous shearing of helium bubbles by Shockley partials leads to twin formation whereas the residual back-stress accumulated from dislocation-bubble interactions assist in detwinning.
      PubDate: 2017-06-16T01:00:29.347648-05:
      DOI: 10.1002/adem.201700357
       
  • Densification and Crystallization in Fe–Based Bulk Amorphous Alloy Spark
           Plasma Sintered in the Supercooled Liquid Region 
    • Authors: Tanaji Paul; Ashish Singh, Sandip P. Harimkar
      Abstract: Spark plasma sintering of Fe48Cr15Mo14Y2C15B6 bulk amorphous alloy at a range of temperatures in the supercooled liquid region (SLR) and above yielded near fully dense compacts. Upon sintering in the temperature range of 570–630 °C in SLR, large increments in density are observed due to enhanced sintering resulting from drastic reduction in the viscosity of the alloy. Above 630 °C, the absence of sufficient driving force for sintering and stiffening of the amorphous matrix from partial crystallization leads to sluggish densification. Analysis of the temperature profile in the sample and the die reveals that the temperature at the center of the sample is higher than that at the inner wall of the die as recorded by the thermocouple and the difference between the two is estimated to be between 31 and 53 °C.Spark plasma sintering of Fe48Cr15Mo14Y2C15B6 bulk amorphous alloy in the supercooled liquid region and above results in large densification upto 630 °C, due to reduction in viscosity and sluggish thereafter upto 800 °C due to (Fe,Cr)23(C,B)6 nanocrystallization induced matrix stiffening. The difference between the temperature at the center of the sample and that measured by the thermocouple is 31–53 °C.
      PubDate: 2017-06-16T01:00:22.596788-05:
      DOI: 10.1002/adem.201700224
       
  • Mechanical Behavior and Adhesion of the Ti/Cr/Au Metallization Scheme on
           Diamond Substrate
    • Authors: Sabeur Msolli; Joel Alexis, Heungsoo Kim
      Abstract: The mechanical properties of a Ti/Cr/Au metallization system deposited on a heavily doped diamond substrate are evaluated, first using nano-indentation tests. Various kinds of conditions are adopted, such as small and high force loadings. These tests are completed by in situ scanning electron microscopy observations of the surface. The adhesion of such multilayer on the diamond substrate is assessed using nano-scratching tests. The profiles of the obtained scratches are analyzed to detect any singularities or defects. Finally, a cross-section topography is performed, in order to obtain the cross profile of the scratch, and to determine the scratch hardness parameter of the metallization system. The Ti/Cr/Au metallization system is a potential candidate to play the role of ohmic contact on diamond. Therefore, its adhesion to diamond is important, since the whole power electronic assembly is mainly subjected to thermal cycling during service. The metallization system must adhere well to diamond, so as to resist temperature gradients and thermal strains that are widely observed in extreme thermal conditions. Otherwise, debonding phenomena may occur, and the whole electronic packaging fail.After the deposition of Ti/Cr/Au metallization system on diamond, microstructural analyzes of the deposit using SEM observations, EDX analysis, and EDS mapping show no viewable defects on the deposit surface. Nano-indentation tests prove that the deposit has a good mechanical behavior under mechanical loading. Finally, nano-scratching tests attest of the good adhesion of the deposit on diamond (see figure).
      PubDate: 2017-06-14T15:32:00.481262-05:
      DOI: 10.1002/adem.201700109
       
  • Dynamic Corrosion and Material Characteristics of Mg–Zn–Zr Mini-Tubes:
           The Influence of Microstructures and Extrusion Parameters
    • Authors: Da-Jun Lin; Fei-Yi Hung, Heng-Jui Liu, Ming-Long Yeh
      Abstract: In this study, magnesium–zinc–zirconium (Mg–Zn–Zr) alloy mini-tubes that fit the diameter of cardiovascular stents are successfully fabricated using an isothermal extrusion method. The influence of extrusion temperature and ram speed on the microstructure are examined. In addition, this research develops a novel dynamic-corrosion apparatus for Mg alloy mini-tube examination, and supplemented with electrochemical, and biocompatibility tests, the optimal criteria for mini-tube extrusion are defined. The optimized specimen not only retains a homogeneous fine-grained structure with a grain size of about 2 µm, but also possesses 300 MPa yielding strength and nearly 15% elongation. Compared with a coarse-grained microstructure, the fine-grained specimens significantly reduces the corrosion and oxidation rates in a dynamic-flow field, resulting in favorable characteristics of degradation, cytocompatibility, and hemocompatibility. The results suggest that precisely controlling the extrusion process can improve the mechanical properties as well as the biocompatibility of Mg alloys for application in cardiovascular implants.The Mg mini-tube is developed for cardiovascular stent application. The extrusion parameter dominates the microstructure, which results in a significant increase in enhanced mechanical properties and corrosion resistance. A new dynamic corrosion test is performed in order to determine the practicability of fine-grained Mg mini-tube.
      PubDate: 2017-06-14T01:56:13.023829-05:
      DOI: 10.1002/adem.201700159
       
  • Influence of Foam Morphology on Effective Properties Related to Metal Melt
           Filtration 
    • Authors: Eric Werzner; Martin Abendroth, Cornelius Demuth, Christoph Settgast, Dimosthenis Trimis, Hartmut Krause, Subhashis Ray
      Abstract: In this article, a numerical study on the sensitivity, related to the performance of open-cell foams used for the depth filtration of liquid metals, on two characteristic morphological properties is presented. Therefore, simulations of fluid flow and particle transport inside an artificial foam structure are carried out, whose porosity and strut shape is varied within a certain expected range. For comparison purposes, however, the simulations are also performed for three typical ceramic foam filters (CFF) with pore densities of 20 and 30 PPI, whose geometries are obtained from CT scans. In order to allow for a comparison between the different structures, a reference length is introduced that relies upon the actual ratio of pores per volume. The evaluation is mainly based on the comparison of the hydraulic tortuosity, the viscous and the inertial permeability coefficients as well as the initial filtration coefficient for alumina inclusions, with their size ranging from of 10 to 40 μm at process conditions typically encountered during the aluminum filtration. It is shown that the ratio of filtration coefficient and pressure drop increases with the porosity, while the material distribution between the struts and the joints is less influential. Finally, the article also provides information on the anisotropy of CFFs and on the transition behavior from steady to unsteady flow in open-cell foams.This article presents a numerical investigation on the sensitivity of permeability, hydraulic tortuosity, and filtration coefficient of open-cell foams used for metal melt filtration regarding their porosity and strut shape for conditions typically observed during the continuous casting of aluminum. The predicted results are compared against three samples of real ceramic foam filters obtained through CT scanning.
      PubDate: 2017-06-13T08:06:18.790058-05:
      DOI: 10.1002/adem.201700240
       
  • Intermetallic Sludge Formation in Fe Containing Secondary Al–Si Alloys
           Influenced by Cr and Mn as Preparative Tool for Metal Melt Filtration
    • Authors: Björn G. Dietrich; Hanka Becker, Michal Smolka, Andreas Keßler, Andreas Leineweber, Gotthard Wolf
      Abstract: In view of filtration of Fe-enriched intermetallics to decrease Fe content in secondary aluminum alloys, the formation of so-called sludge particles has been investigated depending on dwell time and chemical composition using an AlSi9Cu3 secondary alloy with high Fe content. To evaluate the dwell time dependency, samples are cast into ceramic crucibles and held at 620 °C for varying times. Furthermore, Mn and Cr have been added to the melt in different amounts and the alloys are treated for 6 h at 620 °C. The samples are analyzed using light optical micrographs and image analysis to reveal particle sizes and distribution as well as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and electron backscatter diffraction (EBSD) for phase identification. It is found that the growth of Fe containing sludge particles stagnates after reaching a specific value and is not significantly affected by ultra-long dwell times. Mn addition has a minor effect on the the particle size distribution preserving large particle sizes, whereas Cr addition leads to a smaller sludge particles. Generally, the sludge consists of the cubic α-phase. Additionally in the presence of Cr, Fe, and Cr concentration gradients occur in the cubic α–Al–(Fe,Mn,Cr)–Si phase and the Al13Cr4Si4-phase is contained in the centers of the sludge particles. It is concluded that Mn addition is favored due to larger particle size and higher efficiency to bind Fe in the α-phase than by Cr or Cr and Mn addition.In view of a future application of novel filter materials for filtration of iron containing intermetallic phases so called “sludge” to reduce Fe-content in secondary aluminum alloys, the formation of sludge particles depending on melt treatment and varying amounts of Mn and Cr is investigated.
      PubDate: 2017-06-09T14:46:08.728656-05:
      DOI: 10.1002/adem.201700161
       
  • Effect of Directional Solidification Variables on the Microstructures of
           Single-Crystal Turbine Blades of Nickel-Based Superalloy
    • Authors: Fu Wang; Zining Wu, Dexin Ma, Andreas Bührig-Polaczek
      Abstract: Single-crystal turbine blades of nickel-based superalloy are directionally solidified at different withdrawal rates of 0.0017 cm s−1–0.01 cm s−1 aiming to investigate the evolution of as-cast microstructures. The results show that the average primary and secondary dendrite arm spacings, λ1¯ and λ2¯, decrease with increasing withdrawal rate, although the complicated geometry of the blades results in local nonhomogeneity of dendrite arm spacings. The experimentally achieved values of λ1¯ can be reasonably predicted by Ma and Sahm's theoretical model, in which the effect of the secondary dendrite on the primary dendrite arm spacing is considered. With increasing withdrawal rate, the shape of the γ/γ′ eutectic varies from a large block-like eutectic island to an interconnected small strip-like morphology. In addition to this, the average size of the γ/γ′ eutectic gradually decreases with increasing withdrawal rate. A reduction in the average sizes of the γ′ precipitates in the dendrite core and interdendritic region is also observed with increasing withdrawal rate. The microsegregation levels of Al, Ti, Ta, Cr, Co, and Mo are alleviated with increasing withdrawal rate.SC blades are directionally solidified at various withdrawal rates (V) to study the evolution of microstructures. The microstructures are refined with increasing V, although the geometry of blades results in local nonhomogeneous microstructures. λ1¯ can be predicted by Ma and Sahm's model. The microsegregation levels of alloying elements are alleviated with increasing V.
      PubDate: 2017-06-09T14:46:06.528927-05:
      DOI: 10.1002/adem.201700297
       
  • Influence of Torsion Route on the Microstructure and Mechanical Properties
           of Extruded AZ31 Rods
    • Authors: Bo Song; Xiaogang Shu, Hucheng Pan, Guoqiang Li, Ning Guo, Tingting Liu, Linjiang Chai, Renlong Xin
      Abstract: Torsion deformation is an effective and simple technique to tailor the mechanical properties of Mg alloys. In this study, the influences of torsion route on microstructure and mechanical properties of AZ31 rods are investigated. The maximum torsion angle is set as 180° and the two-pass torsion at different torsion routes, twice-successive unidirectional torsion (TA) and reciprocating torsion (TB), is used to process the Mg alloy rods. It is found that the mechanical properties and yield asymmetry are very sensitive to the torsion route. Route TA is more effective for the enhancement of compressive yield strength and the improvement of yield asymmetry, while route TB is more effective for the enhancement of tensile yield strength. It is mainly attributed to the different textural evolutions between the two torsion routes. The relevant mechanisms are addressed and discussed.Torsion deformation is an effective and simple technique to tailor the mechanical properties of Mg alloys. It is found that the mechanical properties and yield asymmetry are very sensitive to the torsion route. Route TA is more effective for the enhancement of compressive yield strength and the improvement of yield asymmetry, while route TB is more effective for the enhancement of tensile yield strength.
      PubDate: 2017-06-09T07:40:27.919944-05:
      DOI: 10.1002/adem.201700267
       
  • Increased Mechanical Stability and Thermal Conductivity of Alumina
           
    • Authors: Stefan Rannabauer; Gerrit-Maximilian Söffker, Marcel Scheunemann, Ulf Betke, Michael Scheffler
      Abstract: Infiltration processing of reticulated porous alumina ceramics (RPC) from reticulated foam manufacturing is investigated by micro computed tomography. Infiltration is carried out with colloidal alumina slurries. Successful infiltration is found to be a function of the RPCs starting microstructure and the particle size of the alumina in the colloidal infiltration system. Suitable infiltration conditions are specified. As a result, RPCs with a low relative density show a fivefold compressive strength after infiltration, as compared to their non-infiltrated RPC counterparts. The highest strength of infiltration processed alumina RPCs at a porosity of 90% is found to be 1.6 MPa, and besides a significant increase of the compressive strength, the thermal conductivity is improved to be 1.5 W m−1 K−1 after infiltration.Infiltration of RPC with colloidal alumina slurries is investigated with respect to the colloidal particle size. Classifying the RPCs’ pore system into different pore orders, the distribution of the colloidal particles is examined by micro computed tomography. The infiltration results in a significant improvement of the struts and thereby the RPC.
      PubDate: 2017-06-09T07:35:27.227864-05:
      DOI: 10.1002/adem.201700211
       
  • Accumulative Roll Bonding at Room Temperature of a Bi-Metallic
           AA5754/AA6061 Composite: Impact of Strain Path on Microstructure, Texture,
           and Mechanical Properties 
    • Authors: Kevin Verstraete; Hiba Azzedine, Anne-Laure Helbert, François Brisset, Djamel Bradai, Thierry Baudin
      Abstract: Accumulative roll bonding (ARB) is performed at room temperature on an aluminum composite up to five rolling cycles, using two different paths: the conventional one (ARB) and the cross ARB (CARB) one consisting of a 90° rotation of the rolling direction before each rolling pass. The microstructure is refined faster by CARB than by ARB occasioning higher yield strength of the elaborated samples. Besides, CARB has the ability to delay the loss of stratification of the composite. The resulting textures are different: while ARB promotes typical rolling components (Brass {011}, Goss {110}, Dillamore {4 4 11}), S {123}), CARB promotes the ND-rotated Brass {011} instead of Brass together with the S and Dillamore components. A Visco-Plastic Self-Consistent (VPSC) simulation highlights that the ND-rotated Brass had Brass and S components for origin. The ND-rotated Brass presence in the texture promotes a better mechanical isotropy of the composite sheet.Accumulative Roll Bonding (ARB) on dissimilar alloys leads to an enhancement of the strength, but the typical fracture of the hard phase interfere with this evolution. A rotation of the sample between each rolling (using CARB) may delay this issue. Besides, two consequences of this rotation are significant: an enhancement of the composite's strength and an original texture.
      PubDate: 2017-06-08T04:45:30.717688-05:
      DOI: 10.1002/adem.201700285
       
  • Novel Heating Elements for Induction Welding of Carbon Fiber/Polyphenylene
           Sulfide Thermoplastic Composites
    • Authors: Rouhollah Dermanaki Farahani; Martine Dubé
      Abstract: Conductive films of carbon nanofibers (CNFs) decorated/coated with metals, either silver (Ag) or nickel (Ni) are fabricated using a solution casting process and used as novel heating elements (HEs) for induction welding of carbon fiber/polyphenylene sulfide (CF/PPS) thermoplastic composites. Prior to making the films, the metal-coated CNFs are prepared by an electroless plating method using Ag or Ni precursors. A solution of the metal-coated CNFs is then casted onto a pure PPS film to give a robust conductive film upon solvent evaporation and annealing in an oven at 200 °C. SEM observation and electrical resistivity measurements reveal that the CNFs are successfully coated with the metals which result in a significant decrease of the films’ electrical resistivity. A third type of HE is also fabricated by solution mixing Ag-coated CNFs and magnetic Fe3O4 nanoparticles. The welding efficiency of the fabricated films is assessed for induction welding of two different types of thermoplastic composites, that is, unidirectional pre-impregnated 16 plies ​​of CF/PPS compression-molded in a quasi-isotropic stacking sequence and 8-ply of satin weave fabric CF/PPS compression-molded in a cross-ply stacking sequence. The mechanical apparent lap shear strength (LSS) of the induction-welded joints is evaluated for the fabricated HEs and compared with the LSS of joints welded using conventional stainless steel mesh susceptors. Under similar testing conditions, Ag-coated CNFs HEs lead to the highest LSS with an average value of ≈31.5 MPa. In general, the new HEs result in superior LSS and higher heating rates when compared to the metallic mesh counterparts. The present work offers a new perspective to push the boundaries toward high quality welding of thermoplastic composites using nanomaterials-based HEs.Novel heating element (HE) types are developed and used for induction welding of thermoplastic composites. The HEs are fabricated using carbon nanofibers (CNFs) that are coated/decorated with metals, either silver or nickel by an electroless plating method. The realization of such HEs leads to the achievement of high quality welding with mechanical apparent lap shear strength values exceeding that obtained for the commonly-used stainless steel mesh susceptors.
      PubDate: 2017-06-07T08:00:14.307129-05:
      DOI: 10.1002/adem.201700294
       
  • Surface Engineered Nanoparticles: Considerations for Biomedical
           Applications
    • Authors: Angie S Morris; Aliasger K Salem
      Abstract: The development of reproducible methods for the fabrication of nanoparticles in the 21st century is a major scientific achievement. Currently, there are many well-established methods for the production of nanoparticles of different shapes, sizes, and compositions. Along with these advancements in nanotechnology, nanoparticles have emerged as excellent tools for a diverse range of applications and have become a focus of research globally. With fundamental research being established, efforts are now being directed toward intelligently designed nanoparticles in which the properties of the nanomaterial are finely tuned depending on the application of interest. Usually, this involves the functionalization of the nanoparticle surface with a ligand. In this review, the impact of nanoparticle surface chemistry is discussed as it applies to biological systems.This review summarizes the current approaches for modifying nanoparticle surfaces and the impact on biological systems. Contained in this writing is a wide variety of examples where ligands (such as drugs, polymers, or proteins) are used to tailor the properties of nanoparticles for various biologically-related applications. These applications include targeted drug delivery, biomedical imaging, or the design of safer and more biocompatible nanomaterials.
      PubDate: 2017-06-07T08:00:10.740916-05:
      DOI: 10.1002/adem.201700302
       
  • Cantilever with High Aspect Ratio Nanopillars on Its Top Surface for
           Moisture Detection in Electronic Products
    • Authors: Nguyen Van Toan; Masaya Toda, Takumi Hokama, Takahito Ono
      Abstract: This work reports the patterning silicon pillars by metal-assisted chemical etching (MACE) process as a post process on a silicon cantilever for a moisture detection. Although the cantilever is very fragile, the patterning of the pillar structures on the cantilever has been successfully demonstrated. The cantilever coated with a material absorbing water (such as polyimide and mesoporous silica) can use as a humidity sensor. Its bending is due to the surface stress change from water molecule absorption. However, the bending of the cantilever is usually at a small value. Here, the silicon cantilever with high aspect ratio pillars on its surface is proposed, which is expected for a larger bending of the cantilever during the water molecule absorption. The moisture detection utilizes the principle that the pillars stack together based upon the condensation behavior of a water vapor on their surfaces.Patterning high aspect ratio nanopillars on the AFM silicon cantilever for the moisture sensing application by metal assisted chemical etching are investigated. The moisture detection utilizes the principle that the pillars stack together based upon the condensation behavior of a water vapor on its surface.
      PubDate: 2017-06-07T08:00:05.077364-05:
      DOI: 10.1002/adem.201700203
       
  • A Microvascular System for the Autonomous Regeneration of Large Scale
           Damage in Polymeric Coatings 
    • Authors: Ryan C. R. Gergely; Michael N. Rossol, Sharon Tsubaki, Jonathan Wang, Nancy R. Sottos, Scott R. White
      Abstract: Self-healing polymers are capable of self-repair either in response to the damage or through external stimuli, but are limited in their ability to autonomously control the volume of healing agents released, in the length scale of damage they address, and in their ability to respond to multiple damage events. Here, the authors report a novel design for healing agent storage and release for vascular coating systems that allows for complete regeneration of a coating with precise and autonomous control of coating thickness. A variety of healing agent formulations that cure under ambient sunlight are explored and their cure profiles and mechanical properties are reported. In the proposed vascular coating system, the stored healing agent remains stable within the network until large-scale damage (e.g., abrasion) completely removes the protective coating. A precise volume within the network is then released, and cures when exposed to simulated sunlight to reform the protective coating. This coating system facilitates consistent coating thickness and hardness for several cycles of coating removal and regeneration.A new microvascular coating system enables fully autonomous regeneration and control of coating thickness. In response to damage, a prescribed amount of healing agent is released through a pressure responsive surface valve to the damaged surface. Exposure to simulated sunlight cures the healing agent to reform the coating.
      PubDate: 2017-06-07T06:54:32.276753-05:
      DOI: 10.1002/adem.201700319
       
  • Toward Functionally Graded Polymer Foams Using Microfluidics
    • Authors: Jonas Elsing; Aggeliki Quell, Cosima Stubenrauch
      Abstract: Functionally graded polymer foams are of great interest for safety components or interfacial tissue engineering. However, most production methods lack control of the pore size. With the microfluidic technique we are able to introduce a defined pore size gradient in polymer foams using foamed emulsions and emulsions, respectively, as templates.Polymer foams with a defined gradient in pore size and density can be produced using microfluidics. For this purpose, the production parameters of the liquid templates, such as liquid flow rate or gas pressure are varied with time. The graded liquid template can then be polymerized.
      PubDate: 2017-06-07T04:55:31.7294-05:00
      DOI: 10.1002/adem.201700195
       
  • Soft Robotics: Review of Fluid-Driven Intrinsically Soft Devices;
           Manufacturing, Sensing, Control, and Applications in Human-Robot
           Interaction 
    • Authors: Panagiotis Polygerinos; Nikolaus Correll, Stephen A. Morin, Bobak Mosadegh, Cagdas D. Onal, Kirstin Petersen, Matteo Cianchetti, Michael T. Tolley, Robert F. Shepherd
      Abstract: The emerging field of soft robotics makes use of many classes of materials including metals, low glass transition temperature (Tg) plastics, and high Tg elastomers. Dependent on the specific design, all of these materials may result in extrinsically soft robots. Organic elastomers, however, have elastic moduli ranging from tens of megapascals down to kilopascals; robots composed of such materials are intrinsically soft − they are always compliant independent of their shape. This class of soft machines has been used to reduce control complexity and manufacturing cost of robots, while enabling sophisticated and novel functionalities often in direct contact with humans. This review focuses on a particular type of intrinsically soft, elastomeric robot − those powered via fluidic pressurization.This manuscript presents a comprehensive review of the materials, design, and manufacturing of fluidically pressurized intrinsically soft robotics, and set a historical context for their development. The authors then discuss their applications for human interaction and speculate on future composition and use cases.
      PubDate: 2017-05-31T08:57:19.925404-05:
      DOI: 10.1002/adem.201700016
       
  • Investigations of Corrosion Resistance of Laser Separated Open Cell
           Metal 
    • Authors: Robert Baumann; Patrick Herwig, Andreas Wetzig, Eckhard Beyer
      Abstract: Open cell metal foam contributes promising solutions to the light weight design, battery applications, and renewable energy. Still, challenges are present concerning the cutting into a defined shape. Mechanical processes like milling and grinding create surface smearing on the foam, which leads to a loss of their open cell behavior. Laser remote cutting offers a promising solution in order to overcome those challenges. Their investigations consider that this technique has a high potential concerning cutting speed, which is increased by more than 500% compared to state of the art laser separation techniques. Nevertheless, quality improvements regarding spatter formation and fouling or corrosion resistance has to be investigated. This paper offers insight into the viability of remote laser cutting and how quality aspects can be improved.Remote laser cutting offers cut velocities up to 300 m min–1 for open cell metal foam. Note, that the open cell character is still present after machining. In their investigations, salt spray test and alternating climate changing are executed. The laser influences areas exhibit less corrosion behavior. Remote laser cutting shows the best way for sizing open cell metal foams.
      PubDate: 2017-05-30T13:52:23.651528-05:
      DOI: 10.1002/adem.201700107
       
  • Influence of Mesostructure on Mechanical Property of Laminated Ti–Al
           Composites 
    • Authors: Shaoyuan Lyu; Yanbo Sun, Lei Ren, Wenlong Xiao, Chaoli Ma
      Abstract: Laminated Ti–Al composite sheets with different mesostructures have been fabricated through hot pressing. The influence of mesostructure on mechanical properties of the composite is investigated. The results indicate that with the increase of sintering temperature, different mesostructures of composite are obtained, that is, laminated Ti/Ti–Al composite, laminated Ti3Al/TiAl composite, and monolithic Ti3Al/TiAl composite. The mechanical properties tests reveal that laminated Ti/Ti–Al composite exhibits better comprehensive mechanical properties, including flexural strength, fracture toughness, and microhardness, than those of laminated Ti3Al/TiAl composite and monolithic Ti3Al/TiAl composite. The fracture analysis shows that the propagation route of crack is zigzag for Ti/Ti–Al composite, curving for laminated Ti3Al/TiAl composite, and approximately a straight line for monolithic Ti3Al/TiAl composite. The relevant strengthening and toughening mechanism of the composites is discussed.Incorporating one ductile layer into the brittle Ti–Al composite is a potential way to overcome low ductility and fracture toughness at room temperature. By controlling the mesostructures of the composite, three types of composites are obtained, among which, laminated Ti/Ti–Al composite exhibits better comprehensive mechanical properties than those of laminated Ti–Al composite and monolithic Ti–Al composite.
      PubDate: 2017-05-29T04:31:28.19734-05:0
      DOI: 10.1002/adem.201700070
       
  • Manufacturing and Characterization of Highly Porous Bioactive Glass
           Composite Scaffolds Using Unidirectional Freeze Casting 
    • Authors: Laura M. Henning; Sara Zavareh, Paul H. Kamm, Miriam Höner, Horst Fischer, John Banhart, Franziska Schmidt, Aleksander Gurlo
      Abstract: The aim of this work is the fabrication of bioactive and degradable scaffolds for bone tissue engineering. Freeze casting is used to obtain macropores. Alongside, highly bioactive 45S5 Bioglass, gelatin and chitosan are used as biocompatible binder and stabilizing agent, respectively. By varying the cooling rate between 2 and 4 K min−1 and whether the slurry is allowed to form a gelled network at 7 °C before freeze casting or not, samples with a porosity of 75% are achieved. X-ray tomography analysis shows smallest pore sizes between 73 and 77 µm and a rather lamellar structure parallel to the freezing direction for the non-gelled samples, whereas the gelled samples have smallest pores between 96 and 120 µm and show a rather cellular structure. Compression tests reveal compressive strengths from 2 (non-gelled) to 3 MPa (gelled), while the quasielastic moduli of the gelled samples (44–46 MPa) clearly exceed values of the non-gelled (20–23 MPa). Thus, it is concluded that the modified pore structure caused by the gelling process markedly improves the mechanical properties of the samples. After seven days in SBF under physiological conditions, a calcium phosphate rich layer is detected on the samples surface, revealing the bioactivity of the scaffolds.The combination of gel casting and freeze casting results in better mechanical properties compared to the sole use of the conventional freeze casting technique. Highly porous 45S5 Bioglass/gelatin/chitosan composite scaffolds, which are gel casted before freeze casting, show an increase in the quasielastic moduli by 100% and potentially sufficient pore sizes for applications in bone tissue engineering.
      PubDate: 2017-05-29T04:31:14.910719-05:
      DOI: 10.1002/adem.201700129
       
  • Identifying the Stages during Ultrasonic Processing that Reduce the Grain
           Size of Aluminum with Added Al3Ti1B Master Alloy 
    • Authors: Gui Wang; Matthew S. Dargusch, Dmitry G. Eskin, David H. StJohn
      Abstract: The combined application of UST and Al3Ti1B grain refiner changes the macrostructure of untreated commercial purity aluminum from large millimeter sized columnar grains to equiaxed grains of a few hundred microns. This research reveals three distinct stages that affect the grain size, while UST is applied during melting and solidification. Stage I applied well above the liquidus temperature improves the efficiency of the refiner, possibly by de-agglomeration and wetting of TiB2 particles, and their distribution throughout the melt by acoustic streaming. Stage I is followed by Stage II, where little further improvement occurs. Stage III causes additional grain refinement when applied at and below the liquidus temperature, where nucleation of grains maybe enhanced by cavitation, which can also facilitate fragmentation and detachment of grains formed on the sonotrode. Convection due to acoustic streaming creates a uniformly undercooled temperature in the melt, which ensures the survival of these new grains during transport, as well as assisting the transport of grains to produce a uniform fine grain size throughout the ingot.Termination of ultrasonic treatment of Al with Al3Ti1B master alloy addition at a range of temperatures reveals three stages affecting grain refinement. The grain density is increased by five to ten times during stages I and III, which are above and below the liquidus temperature, respectively. The grain size decreased from 278 to 115 microns after 110 s of treatment.
      PubDate: 2017-05-29T04:30:59.036537-05:
      DOI: 10.1002/adem.201700264
       
  • Effects of Phase Content and Evolution on the Mechanical Properties of
           Mg95Y2.5Zn2.5 and Mg93.1Y2.5Zn2.5Ti1.6Zr0.3 Alloys Containing LPSO and W
           Phases 
    • Authors: Shouzhong Wu; Zhe Zhang, Jinshan Zhang, Chunxiang Xu, Xiaofeng Niu, Wei Liu
      Abstract: The effects of phase content and evolution on mechanical properties of the alloys are investigated by extruding Mg95Y2.5Zn2.5 and Mg93.1Y2.5Zn2.5Ti1.6Zr0.3 alloys with different original microstructures. The 18R-LPSO phase plays a decisive role in the strength of as-extruded alloys. The spherical W-MgYZn2 phase enhances the deformability and ductility of the alloys. The dynamic recrystallization grains can be observed in all as-extruded alloys. However, the 14H-LPSO clusters and dynamic precipitates only form in the as-cast and T41-treated (solid-solution treatment at 530 °C for 3 h with water cooling) alloys after extrusion. Based on synergistic effects of these phases mentioned above, the T41-treated Mg93.1Y2.5Zn2.5Ti1.6Zr0.3 alloy exhibits good compressive mechanical properties after extrusion.The solid-solution treated Mg93.1Y2.5Zn2.5Ti1.6Zr0.3 alloy exhibits good comprehensive mechanical properties after extrusion, which can be attributed to the synergistic effects of these phases, including 18R-LPSO phase, spherical W-MgYZn2 phase, DRX grains, 14H-LPSO clusters, and dynamic precipitates.
      PubDate: 2017-05-26T00:46:22.974917-05:
      DOI: 10.1002/adem.201700185
       
  • Effect of Crucible Material for Ingot Casting on Detrimental Non-Metallic
           Inclusions and the Resulting Mechanical Properties of 18CrNiMo7-6 Steel 
           
    • Authors: Sebastian Henschel; Johannes Gleinig, Tim Lippmann, Steffen Dudczig, Christos G. Aneziris, Horst Biermann, Lutz Krüger, Anja Weidner
      Abstract: The steel 18CrNiMo7-6 (AISI 4317) is treated in three different crucibles based on carbon-bonded alumina. Non-metallic inclusions in the steel are characterized by means of optical microscopy and scanning electron microscopy. Strength, ductility, and dynamic fracture toughness of the steel are evaluated at different temperatures. Furthermore, fatigue lifetimes in the very high cycle regime are determined. The treatment in a carbon-bonded alumina (A–C) crucible resulted in a relatively high inclusion content involving a high number of duplex inclusions consisting of MnS and Si–Al–O. In contrast, less but large pure MnS inclusions are observed when the steel is treated in carbon-bonded alumina-zirconia-titania crucibles – with or without a coating of carbon nanotubes (AZT–C–n and AZT–C). The steel treated in the A–C crucible exhibits the highest strength and fatigue lifetime, but the lowest energy dissipation. The relatively low inclusion content in the AZT–C treated steel results in high energy dissipation during tensile deformation. However, large MnS inclusions in the AZT–C and AZT–C–n treated steels act as crack initiation sites and reduce the fatigue lifetime. The dynamic fracture toughness is not affected by the different melt treatments. This result is explained by cell-like structures within the material that are characterized by a lower strength and an increased concentration of MnS inclusions.The effect of crucible material on the distribution of non-metallic inclusions in 18CrNiMo7-6 steel (AISI 4317) is studied. The resulting quasi-static strength and ductility, the dynamic fracture toughness, and the fatigue life time are evaluated. The treatment in a carbon-bonded alumina crucible results in lowest ductility due to a relatively high inclusion content. However, the highest fatigue strength is observed for this treatment.
      PubDate: 2017-05-24T08:55:39.10871-05:0
      DOI: 10.1002/adem.201700199
       
  • A Combinatorial Approach for Assessing the Magnetic Properties of High
           Entropy Alloys: Role of Cr in AlCoxCr1–xFeNi 
    • Authors: Tushar Borkar; Varun Chaudhary, Bharat Gwalani, Deep Choudhuri, Calvin V. Mikler, Vishal Soni, Talukder Alam, Raju V. Ramanujan, Rajarshi Banerjee
      Abstract: A combinatorial assessment of composition-microstructure-magnetic property relationships in magnetic high entropy AlCoxCr1-xFeNi alloy (0 ≤ x ≤ 1) system has been carried out using compositionally graded alloys fabricated via laser additive manufacturing. At one end, the AlCoFeNi composition (x = 1) consisted of equiaxed B2 grains, exhibiting very early stages of phase separation (only compositional partitioning) into Ni–Al rich and Fe–Co rich regions within grains of the B2 phase. At the other extreme, the AlCrFeNi composition (x = 0) exhibited grains with pronounced spinodal decomposition, resulting in a B2 + bcc microstructure with the degree of spinodal decomposition progressively increasing with Cr content in these AlCoxCr1–xFeNi alloys. While the saturation magnetization (Ms) monotonically increases six times from x = 0 to x = 1, the coercivity (Hc) variation is non-monotonic, increasing seven times from x = 0 to x = 0.4, and subsequently decreasing fourteen times from x = 0.4 to x = 1.0. The magnetic phase transition temperature (Tc) for these alloys also increases monotonically with increasing Co content with a second phase transition exhibited in a certain range of compositions between x = 0.6 to x = 0.8. Such substantial changes in the magnetization behavior and properties of magnetic high entropy systems opens possibilities of tuning these alloys for specific soft or hard magnetic component applications.Laser Engineered Net Shaping (LENS™) process is used for making a compositionally graded magnetic AlCoxCr1–xFeNi HEA (0 ≤ x ≤1). The size scale of phase separation wave, which is affected by the composition, critically affects the magnetic properties like saturation magnetization and coercivity.
      PubDate: 2017-05-24T06:05:39.449627-05:
      DOI: 10.1002/adem.201700048
       
  • Activation Energy and High Temperature Oxidation Behavior of
           Multi-Principal Element Alloy
    • Authors: Harpreet Singh Grewal; Ramachandran Murali Sanjiv, Harpreet Singh Arora, Ram Kumar, Aditya Ayyagari, Sundeep Mukherjee, Harpreet Singh
      Abstract: Activation energy and diffusion kinetics are important in modulating the high temperature oxidation behavior of metals. Recently developed multi-principal element alloys, also called high entropy alloys (HEAs), are promising candidate material for high temperature applications. However, the activation energies and diffusion kinetics of HEAs have been limitedly explored. We investigate the diffusional activation energy for oxidation of Al0.1CoCrFeNi HEA. Compared to conventional steels and Ni-based super alloys, the HEA showed a significantly higher diffusion activation energy. This behavior is explained based on low potential energy of the lattice and interstitial sites which effectively trap the atoms, limiting their diffusion. The atomic mean jump frequency for interstitial diffusion of oxygen in the HEA is four-orders of magnitude lower than T22 and T91 steels and seven-orders of magnitude lower compared to pure iron. Al0.1CoCrFeNi HEA showed the lowest oxidation rate compared to conventionally used steels, super-alloys, and coatings.Al0.1CoCrFeNi high entropy alloy shows significantly high activation energy and oxidation resistance. High activation energy lowers the mean jump rate of oxygen atom resulting in sluggish diffusion.
      PubDate: 2017-05-24T06:05:31.354021-05:
      DOI: 10.1002/adem.201700182
       
  • Sandwich Structures Consisting of Aluminum Foam Core and Fiber Reinforced
           Plastic Top Layers 
    • Authors: Drebenstedt Claudia; Susi Rybandt, Drossel Welf-Guntram, Trautmann Maik, Wagner Guntram
      Abstract: Thinking of new approaches for light weight design with sandwiches, the combination of aluminum foam as core and fiber reinforced plastics as top layers can be a good way to increase the light weight aspect and combine advantages of both materials. For structural applications, often a high bending stiffness and a good damping capability in the combination with the lightweight aspect are needed. For these new sandwiches, especially, the bonding properties are crucial for later applications. Therefore, investigations regarding the bonding properties of the combination of the two components are carried out. The objective is to find a way of combining these materials without adhesives. Different ways of composite manufacturing are tested and compared according to DIN 53292: “testing of sandwiches; tensile test perpendicular to the faces”. Furthermore, different pretreatments of the foam core are compared. These include sandblasting with a chemically modified blasting material, a structure included by a modification of the foaming tool, and untreated foam for comparison reasons to the state of the art. It is found that the structure induced during the foaming step is suitable for adhesive bonding, but not for the other processes. Better results can be expected by further adaption of the implemented structure. The best results in the compression molding process are obtained with the sandblasted foam cores.Aluminum as core and fiber reinforced thermoplastic top layers are combined by compression molding to a new sandwich structure without additional adhesives. Evaluations by tensile tests regarding the bonding depending on the surface pretreatments are conducted. Finally, a demonstrator is realized.
      PubDate: 2017-05-23T04:05:57.298217-05:
      DOI: 10.1002/adem.201700066
       
  • Formation of Corundum, Magnesium Titanate, and Titanium(III) Oxide at the
           Interface between Rutile and Molten Al or AlSi7Mg0.6 Alloy 
    • Authors: Anton Salomon; Claudia Voigt, Olga Fabrichnaya, Christos G. Aneziris, David Rafaja
      Abstract: For the filtration of oxide inclusions in aluminum melts, active materials covering the surface of ceramic filters are developed permanently. In this study, corundum (α-Al2O3) filters coated with rutile (TiO2) coatings are exposed to molten aluminum and to aluminum alloy AlSi7Mg0.6, respectively. For pure aluminum, the chemical reactions occurring at the interface between the metal melt and the filter surface are found to lead primarily to the formation of Al2O3 at the surface of the functionalized filter. Al3Ti and Ti2O3 are found as minor phases for long operation times. In the case of aluminum alloy AlSi7Mg0.6, the surface of the TiO2 coatings is covered by MgTiO3. Additional phases are Al2O3 and Al3Ti. One part of the interface reaction experiments is performed on powder mixtures to identify the reaction products, another one on functionalized filters to estimate the reaction kinetics. The experiments are performed in a Spark Plasma Sintering apparatus, which offers high heating rates that are comparable with those in standard cast processes, but impedes the macroscopic flow of the melt in case of the bulk samples. The equilibrium state is concluded from thermodynamic calculations using the CalPhaD method.Interfacial reactions between rutile and molten pure Al or molten AlSi7Mg0.6 alloy are studied. Microstructural analyses are verified by thermodynamic calculations. TiO2 is reduced leading to the formation of corundum with small amounts of intermediate Ti2O3 (pure Al) or intermediate MgTiO3 preceding corundum (AlSi7Mg0.6). Depending on the contact area, the respective oxide formation inhibits the formation of Al3Ti or (Al,Si)3Ti.
      PubDate: 2017-05-22T06:05:30.885238-05:
      DOI: 10.1002/adem.201700106
       
  • High-Speed Roll-to-Roll Hot Embossing of Micrometer and Sub Micrometer
           Structures Using Seamless Direct Laser Interference Patterning Treated
           Sleeves 
    • Authors: Andreas Rank; Valentin Lang, Andrés Fabián Lasagni
      Abstract: In this study, we present a seamless high-speed roll-to-roll hot embossing process using a direct laser interference patterned nickel sleeve as a mold. Line-like patterns with spatial periods of 5.0, 3.9, and 1.5 μm and structure heights of 572, 325, and 141 nm, respectively are used for imprinting PET-foils. The influence of the web speed on the cavity filling and consequently on the structure height and homogeneity of the fabricated patterns is studied. The web speed is varied between 2 and 50 m min−1. For the 5.0 and 3.9 μm periods, a decrease in structure height with the web speed occurs, while for the 1.5 μm period the structure height remains constant in the tested interval. Also a decrease in homogeneity is observed with increasing web speed. Finally, an analytical model, based on the Navier–Stokes equation and Hertzian contact pressure, is used to explain the experimental results. The experimental data are in good agreement with the calculated theoretical values.A seamless high-speed Roll-to-Roll hot embossing process using a direct laser interference patterned Nickel sleeve as a mold is presented. Line-like periodic patterns with spatial periods of 5.0, 3.9, and 1.5 µm are fabricated directly on metallic sleeves using a two-beam configuration interference set-up. The influence of the web speed on the cavity filling and consequently on the structure height of the patterns produced on the PET foils is analyzed, for web speeds between 2 and 50 m min–1. An analytical model, based on the Navier–Stokes equation and Hertzian contact pressure, is used to explain the experimental results.
      PubDate: 2017-05-22T06:00:40.806103-05:
      DOI: 10.1002/adem.201700201
       
  • On the Indentation Resistance of a PC Layer on PVC Foam Substrate 
    • Authors: Adam M. Boyce; Vikram S. Deshpande, Norman A. Fleck
      Abstract: The indentation response of a polycarbonate face sheet bonded to a PVC foam substrate is investigated experimentally and numerically. The deformation mode involves foam crushing, and membrane stretching of the PC layer at large indenter displacements; this is quantified using optical strain measurement techniques. The bottom corners of the foam substrate lifts off its underlying support when the foam layer is sufficiently thin. Peak load is dictated by tensile failure of the foam on the bottom face. Finite element simulations suggest that a deep foam core prevents this lift-off and results in a greater load carrying and energy absorption capacity.The indentation response of a polycarbonate face sheet bonded to a PVC foam substrate is investigated experimentally and numerically. The deformation mode involves foam crushing, and membrane stretching of the PC layer at large indenter displacements; this is quantified using optical strain measurement techniques. The bottom corners of the foam substrate lifts off its underlying support when the foam layer is sufficiently thin. A deep foam core prevents this lift-off and results in a greater load carrying and energy absorption capacity.
      PubDate: 2017-05-22T06:00:30.223866-05:
      DOI: 10.1002/adem.201700075
       
  • Novel Composite Foam Concept for Head Protection in Oblique Impacts 
    • Authors: Yasmine Mosleh; Jos Vander Sloten, Bart Depreitere, Jan Ivens
      Abstract: Rotational acceleration experienced by the head during oblique impacts is known to cause traumatic brain injuries. It is hypothesized that shear properties of a foam layer, used for head protection (e.g., protective helmet liners, headliners in cars) can be related to the extent of rotational acceleration transmitted to the head. Furthermore, it is hypothesized that by introducing anisotropy in a foam layer, rotational acceleration can be mitigated. In this study, an anisotropic composite foam concept is proposed to mitigate head rotational acceleration, hence reducing the risk of traumatic brain injuries. The composite foam concept introduces anisotropy in a foam at the “macro level”, combining different densities of foam in layered and quasi-fiber/matrix configurations. The performance of expanded polystyrene (EPS) composite foams in quasi-static compression and combined shear-compression loading and also linear and oblique impact experiments, has been compared with the performance of single layer EPS foam of similar thickness and density. The results of oblique head impact have been analyzed by global head injury criteria such as HIC, HICrot, and HIP. The composite foam concept demonstrates a great potential to be utilized in applications such as protective helmets due to the significant mitigation of brain injury risk.In this study, an anisotropic composite foam concept is proposed to mitigate head rotational acceleration, hence reducing the risk of traumatic brain injuries in oblique impacts. The composite foam concept introduces anisotropy in a foam at the “macro level,” combining different densities of foam in layered and quasi-fiber/matrix configurations. This concept can be used, for example, for helmets with complex shapes.
      PubDate: 2017-05-19T06:10:37.998045-05:
      DOI: 10.1002/adem.201700059
       
  • Microstructure and Corrosion Behavior of the Friction Stir Welded Joints
           Made from Ultrafine Grained Aluminum 
    • Authors: Marta Lipińska; Ewa Ura-Bińczyk, Lech Olejnik, Andrzej Rosochowski, Małgorzata Lewandowska
      Abstract: Joints made from ultrafine grained aluminium alloy 1050 are investigated in order to examine the corrosion behavior and microstructural changes between base materials and stir zones. Samples in the initial state, after four and eight passes of Incremental ECAP (I-ECAP) process were joined with similar plates using Friction Stir Welding. Initially refined microstructure after I-ECAP transformed to homogenous few micron sized grains structure in stir zones. AlFeSi particles present in the microstructure became fragmented during plastic deformation and welding process. The observed minor differences in corrosion resistance include slightly higher values of corrosion potentials but more complex pits’ morphology for I-ECAP processed samples comparing to the stir zones.The changes in the microstructure and corrosion resistance between base materials (BM) and stir zones (SZ) are investigated. The number refers to the number of I-ECAP passes of base material. After the corrosion tests, the surface of the samples was examined using SEM. With increasing number of I-ECAP passes, the pits pose more developed structure with linked cavities. For SZ samples, which exhibit higher grain size, the number of pits is reduced. Pits are also less developed but deeper. The number of pits and surface covered by them is connected with size of AlFeSi particles.
      PubDate: 2017-04-18T06:35:59.395926-05:
      DOI: 10.1002/adem.201600807
       
  • Microstructure and Mechanical Properties of Fine Structured B4C/2024 Al
           Composites with High B4C Content 
    • Authors: Ruixiao Zheng; Fengmei Ma, Yitan Zhang, Chaoli Ma
      Abstract: In this study, bulk fine structured B4C/2024 Al composites with various B4C content are prepared by mechanical milling and subsequent hot consolidation. Scanning electron microscopy (SEM) observation revealed that the higher the B4C content, the finer the B4C particle size in the bulk composites. Transmission electron microscopy (TEM) observation indicates that the grain size of the Al matrix around the B4C particles is much finer compared to other, area due to the large difference in coefficients of thermal expansion (CTE) between the Al matrix and the B4C particles. Room temperature compression test reveals that with increasing B4C content, the compression strength of the bulk samples first increases and then decreases. The significant change of the mechanical properties is discussed based on the microstructure observed.Bulk fine grained B4C/2024 Al composites with various B4C content are prepared by mechanical milling and subsequent consolidation. The microstructure of the composites can be divided into three zones depending on the microstructural features, which significantly affect the global mechanical properties of the composites.
      PubDate: 2017-04-18T02:45:29.39602-05:0
      DOI: 10.1002/adem.201700047
       
  • Graphene Platelet (GPL)/Nickel (Ni) Laminate Coatings for Improved Surface
           Properties 
    • Authors: Meng Li; Jian Liu, Xiaoping Zhang, Cunlong Zhou, Sai Priya Munagala, Yaqin Tian, Jie Ren, Kyle Jiang
      Abstract: In this paper, an investigation is reported on graphene platelet (GPL)/nickel (Ni) laminate coatings by electrochemical deposition. Nickel sulphamate baths with and without GPLs are used to produce GPL/Ni coatings with varied layers and pure Ni coatings for comparison. Microstructures, surface roughness, and mechanical performance of the coatings were examined. It is found that GPLs are homogeneously deposited in the Ni matrix. With the addition of GPLs, the surface roughness of the GPL/Ni composites increases while the average grain size of the Ni matrix decreases significantly. A higher hardness of coatings can be obtained by depositing more layers and introducing a higher content of GPLs. The microstructure of GPL/Ni composite coatings exhibits a preferred orientation at (111).In this paper, an investigation is reported on graphene platelet (GPL)/nickel (Ni) multilayer coatings by electrochemical deposition. The schematic of structure of coatings is shown in ToC figure. The research shows the potential of GPLs, as nano fillers for fabrication of composite coatings with excellent mechanical performance, and the preparation of multilayer composites can provide a new way to prepare new composite materials.
      PubDate: 2017-04-18T02:40:30.19909-05:0
      DOI: 10.1002/adem.201600795
       
  • Synthesis, Microstructure, and Catalytic Performance of Monolithic
           Low-Density Porous Au 
    • Authors: Qin Li; Lixian Lian, Ying Liu, Chaoqing Liu
      Abstract: A series of monolithic porous Au with different pore sizes are successfully synthesized by a facile template-dealloying corrosion method. Spherical Cu particles are employed as sacrificial templates, and a FeCl3–HNO3 two-step corrosion method is developed to dissolve the Cu components. The microstructure and phase evolution, as well as the effect of the corrosive media, are investigated in this study. As a result, the prepared monolithic porous Au possesses ultra-low density and a special hollow porous core-shell structure. When a small-sized template (≈1 μm) is adopted, the corresponding density is as low as 0.37 g cm−3 (1.8% of the full density of Au). In addition, due to the special structure, the monolithic porous Au exhibits good catalytic performance (Kapp = 0.43 min−1), that is, relatively higher than that of most traditional Au-based powder/slurry materials.A series of monolithic porous Au with different pore sizes are successfully synthesized using spherical cu particles, as a new kind of sacrificial templates. A Fecl3–HNO3 two-step corrosion method is developed to dissolve the Cu components. The prepared porous Au bulks possess ultra-low density as low as 0.3 g cm−3 and hollow porous core-shell structure, exhibiting excellent catalytic performance as monolithic catalysts.
      PubDate: 2017-04-18T02:35:40.548879-05:
      DOI: 10.1002/adem.201700045
       
  • Brazing Graphite to Aluminum Nitride for Thermal Dissipation
           Purpose 
    • Authors: Tsung-Te Chou; Wei-Hsing Tuan, Hiroshi Nishikawa, Biing-Jyh Weng
      Abstract: In the present study, graphite paper is joined to aluminum nitride (AlN) using an active Ag–Cu–Ti foil. The Ti in the brazing foil diffuses to AlN side to form titanium nitride, to graphite side to form titanium carbide during bonding. The thermal diffusivity of the AlN–AgCuTi graphite joint is double that of AlN substrate; the resulting thermal conductivity of the joint is, thus, higher. Though the flexural strength of the joint is half that of AlN substrate, it can deflect for 1 mm at a 28 mm span without failure. The large deflection capability can be related to the sliding between graphite sheets within the graphite paperIn the present study, graphite paper is joined to aluminum nitride (AlN) using an active Ag–Cu–Ti foil. The AlN–Ag–Cu–Ti graphite joint exhibits unique thermal and mechanical characteristics.
      PubDate: 2017-04-13T10:11:01.381013-05:
      DOI: 10.1002/adem.201600876
       
  • Continuous Casting of TiAlNb Alloys with Different Velocities by Mixing
           Binary TiAl Ingot and Nb Wire 
    • Authors: Hong-Ze Fang; Rui-Run Chen, Dong Chai, Yao-Hua Yang, Yan-Qing Su, Hong-Sheng Ding, Jing-Jie Guo, Heng-Zhi Fu
      Abstract: A method of continuous casting is used and the research investigates microstructure and mechanical properties under different drawing velocity (R, mm/min). The results show that microstructure and composition measurement of different zones are uniform. The smallest grain size is 25.93 μm and formability is good with 0.5R. Compressive strength is higher with 0.5R and maximum value is 1697MPa. Fracture toughness with 0.5R improves about 35.7% which is 21.7MPa·m1/2. The fracture morphology is trans-lamellar fracture and interface de-lamination. The method is a feasible way to continuously cast the TiAl-Nb alloys. The R is an important parameter to add high-melting-point element, which affects solidified temperature interval of solidification front and electromagnetic stirring.A method is used to add high-melting-point element into TiAl-based alloy. Microstructure and composition measurement are uniform of liquid phase zone, mushy zone and stability zone with 0.5R. Another image is compressive strength and fracture toughness with different drawing velocity.
      PubDate: 2017-04-10T06:21:24.318075-05:
      DOI: 10.1002/adem.201700058
       
  • Reproducible Superhydrophobic PVC Coatings; Investigating the Use of
           Plasticizers for Early Stage Biofouling Control
    • Authors: Robert Brown; Sonia Russell, Salina May, Fiona Regan, James Chapman
      Abstract: Here we show an easy to synthesize superhydrophobic material using a solvent phase–separation process of poly vinyl chloride. It is found that solvents mixed in different ratios increase the dielectric value of the solvent and can be tuned to produce superhydrophobic PVC. The PVC solution is then spin-coated onto glass slides for characterization using scanning electron microscopy. Plasticizers are doped into the 70% (v/v) PVC to determine their overall effects; it is found that plasticizers reduce the water contact angle value. The final coatings were tested in a series of antifouling assays in a marine environment lab study; it is found that the superhydrophobic PVC material reduced marine biofouling.The paper investigates the influence of surface hydrophobicity as a mechanism to reduce early stage marine biofouling. A solvent phase separation process to produce superhydrophobic water contact angle values (>150°) is performed and the materials show less early stage marine biofouling.
      PubDate: 2017-04-07T03:42:05.577989-05:
      DOI: 10.1002/adem.201700053
       
  • Nanoporous Surface Modifications through Dealloying of Al–Ti
           Alloy 
    • Authors: Wei Zhao; Nianqi Liu, Jiacheng Rong, Lei E, Dan Zhao
      Abstract: TiO2 nanoporous structure was formed on the surface of Al–Ti alloy through a facile chemical corrosion method. The alloy composition, NaOH concentration, reaction time, and temperature played important roles in determining the morphology, elemental composition, phase composition, and the hydrophilic properties of the as-dealloyed samples. A uniform pore size distribution of a three-dimensional network structure was obtained with the diameter ranged from 100 nm to 2 μm. The obtained TiO2-based crystalline material exhibited good surface hydrophilic activity and light absorbency, which opened avenues in formation of porous nanostructures with high performance and low cost.A facile method for modifying TiO2 nano-porous surface is presented by chemical corrosion of Al–Ti alloy. The pores with three-dimensional continuous network in surface can be developed through controlling the Al content and alkali concentration, which may lead to a good surface hydrophilicity and light absorbance.
      PubDate: 2017-04-06T08:16:29.395702-05:
      DOI: 10.1002/adem.201600866
       
  • A Micromechanical Approach Investigating the Effects of Percolating
           Eutectic Network on Mechanical Behavior of Magnesium Alloys
    • Authors: Bao Zhang
      Abstract: A novel two-dimensional (2D) micromechanical model presented is capable of predicting eutectic network strength and structural efficiency consistent with computed results on the basis of three-dimensional (3D) actual morphology of eutectic network, and shows considerable advantages in terms of efficiency, practicability and computation cost. Another critical advantage lies in the capability of evaluating network-matrix interaction and the incorporation of interaction strength leads to an improved agreement between numerical and experimental flow behavior of the Mg alloy. The analysis also suggests that network-matrix interaction is comparable with dispersion and network strengthening with respect to the contribution to alloy yield strength.A micromechanical model proposed is capable of assessing the deformation behavior and structural efficiency of eutectic network formed in high pressure die cast Mg alloys, and more importantly, reveals the strength due to network-matrix interaction, that is, comparable with other strengthening effects.
      PubDate: 2017-04-06T08:16:27.310402-05:
      DOI: 10.1002/adem.201600871
       
  • Influence of Erbium, Cerium on the Stress Corrosion Cracking Behavior of
           AZ91 Alloy in Humid Atmosphere 
    • Authors: Yulai Song; Zhen Wang, Yaohui Liu, Miao Yang, Qingxiang Qu
      Abstract: AZ91 magnesium alloys modified by Er and Ce are fabricated (referred to as AZErCe) and their stress corrosion cracking (SCC) behaviors are studied by slow strain rate tensile (SSRT) method in air, humid atmosphere with and without chloride. The addition of Er and Ce promotes the formation of Al3Er and Al11Ce3 phase and reduces both the size and the volume fraction of β-phase. AZErCe possess improved corrosion resistance and passivation characteristic compared to AZ91 due to the reduced micro-galvanic corrosion and the more protective films. SSRT tests demonstrate that the joint addition of Er and Ce effectively improve the SCC resistance of AZ91 alloy. In particular, the representative fractography of AZErCe exhibits lesser effect of hydrogen embrittlement than AZ91. The improved SCC resistance of AZErCe can be ascribed to the presence of Er and Ce, which alleviate corrosion of Mg matrix and thus weaken the effect of hydrogen embrittlement on SCC resistance.Compared with the microstructure of as-cast AZ91 alloy, the addition of Er and Ce can significantly reduce the volume fraction and the size of β-phase and facilitate the formation of Al3Er and Al11Ce3 intermetallic compounds, which are easily distinguished by white color from gray β-phase. All of these changes exert positive effect on SCC resistance of AZ91 alloy.
      PubDate: 2017-04-05T07:55:57.202949-05:
      DOI: 10.1002/adem.201700021
       
  • Tough Nano-Architectured Conductive Textile Made by Capillary Splicing of
           Carbon Nanotubes 
    • Authors: Yue Liang; David Sias, Ping Ju Chen, Sameh Tawfick
      Abstract: Flexible electronics require electrically conductive and mechanically reliable nanoscale thin films. However, thin metal films have low fracture energy, which limits the performance of flexible devices. We demonstrate the design and synthesis of highly conductive, strong and tough nano-architectured textile by capillary splicing of aligned carbon nanotubes (CNT). Owing to the strong van der Waals forces among CNTs, the pristine CNT network has average strength of 170 MPa. The average fracture energy of the textile is 16 kJ/m2, 50 folds higher than metal nanofilms. The high toughness results from crack bifurcations and friction hysteresis in a dissipation zone propagating several millimeters ahead of the crack tip. This material is suitable for applications ranging from smart skin and flexible sensors.Flexible electronics require thin conductive and structurally reliable materials. However, thin metal films have low fracture energy and limited ductility. A bio-inspired design is demonstrated for the fabrication of strong, tough, and highly conductive carbon nanotube textile based on a nano-architectured network. The architectured textile has a fracture energy 50 folds higher than thin metal films at a fraction of the density.
      PubDate: 2017-04-05T03:55:42.229035-05:
      DOI: 10.1002/adem.201600845
       
  • Developing Breathable Double-Layered Fibrous Membranes Equipped with Water
           Pulling Mechanism Toward Clothing with Enhanced Comfort
    • Authors: Hossein Fashandi; Amir Reza Ghomi
      Abstract: Quick transfer of sweat from skin to atmosphere and dryness of textile inner surface are of scientific and commercial interests. However, creating a balance between these two parameters remains a serious challenge. In this work, electrospun double-layered membranes constructed of poly(vinylidene fluoride) fibrous layer (as inner hydrophobic layer) and nylon6 nanofibrous layer (as outer hydrophilic layer) are produced. Once a thin hydrophobic layer is considered, the enhanced water pulling mechanism is balanced out by increased wetted area in the inner surface. This is handled through selecting an optimum thickness for the inner layer. The designed double-layered membrane is a promising candidate for developing modern breathable textiles with enhanced moisture management properties such as sportswear.Developing electrospun fibrous structures with the ability of quick sweat transfer from skin to atmosphere and dryness of inner surface is the main goal of the present research work. This is implemented through manufacturing double-layered fibrous membranes composed of a poly(vinylidene fluoride) hydrophobic layer and a nylon6 hydrophilic layer. The produced sample is a promising candidate for developing modern breathable textiles such as sportswear.
      PubDate: 2017-04-05T03:51:12.317096-05:
      DOI: 10.1002/adem.201600863
       
  • Initiated Chemical Vapor Deposition of Polymer Films at High Process
           Temperature for the Fabrication of Organic/Inorganic Multilayer Thin Film
           Encapsulation 
    • Authors: Bong Jun Kim; Hyejeong Seong, Hyunjeong Shim, Young Il Lee, Sung Gap Im
      Abstract: For the fabrication of thin film encapsulation (TFE), sequential deposition of organic and inorganic layers is inevitable. A single-chamber system of initiated chemical vapor deposition (iCVD) and atomic layer deposition (ALD) is reported previously. Here, the substrate temperature (Ts) of the iCVD is aligned with that of ALD to facilitate the transition of the deposition mode by removing delays caused by repeated heating/cooling of the substrate. While increasing the Ts of iCVD from 40 to 90 °C, the process pressure is optimized so that the properties of the organic film are unchanged from that deposited with 40 °C. The Ts alignment significantly reduced the time delay during transition of the deposition mode, and the fabrication of the TFE is expedited.Within a single-chamber system capable of both initiated chemical vapor deposition (iCVD) and atomic layer deposition (ALD) processes, the substrate temperature of iCVD is increased to 90 °C to equalize the process temperature with ALD. The transition between organic and inorganic layer deposition modes is facilitated without any loss of barrier property of the fabricated multilayer thin film encapsulation.
      PubDate: 2017-03-31T07:10:30.288291-05:
      DOI: 10.1002/adem.201600870
       
  • Inkjet and Aerosol Jet Printing of Electrochemical Devices for Energy
           Conversion and Storage 
    • Authors: L. Jay Deiner; Thomas L. Reitz
      Abstract: Inkjet and aerosol jet printing have recently emerged as promising fabrication techniques for a broad range of devices for electrochemical energy conversion and storage – batteries, fuel cells, and supercapacitors. If fully realized, these printing techniques may enable device performance advantages accruing from precise micron scale patterning, thin layer deposition, and materials grading. Printing may also allow scalable, low materials waste manufacturing, and conformal integration of power elements into structural elements. This article reviews the fundamental capabilities of inkjet and aerosol jet printing relevant to electrochemical devices, surveys current literature, and presents future challenges which must be tackled to achieve high performance, printed electrochemical energy storage, and conversion devices.Inkjet and aerosol jet printing are emerging methods for the fabrication of batteries, fuel cells, and supercapacitors. These direct-write methods show particular promise because they enable low cost, conformal deposition of materials within the lengthscales that are important for electrochemical device performance improvement and structural integration. At the macroscale, inkjet and aerosol jet printing allow for maskless deposition on a range of substrates. At the mesoscale, they facilitate functional grading at and beyond electrode/electrolyte interfaces. At the microscale, they permit thin layer deposition and extension of the electrode/electrolyte interfacial area.
      PubDate: 2017-03-31T07:05:48.222431-05:
      DOI: 10.1002/adem.201600878
       
  • Effects of Solution Treatment on the Microstructure and Mechanical
           Properties of Ti–22Al–25Nb Alloys 
    • Authors: Yang Wu; Hongchao Kou, Bin Tang, Degui Liu, Jizhen Li, Jinshan Li
      Abstract: The effects of solution treatment on the microstructure and mechanical properties of Ti-22Al-25Nb alloy are investigated. Numerous equiaxed α2 particles distribute in a B2 matrix after solution treatment in the α2 + B2 region. The growth rate of the B2 grain increases with solution temperature and decreases with increasing holding time. When the solution temperature is lower than B2-transus, it is seen that both the strength and ductility decrease with increasing solution temperature and holding time. After being solution-treated at a super-transus temperature, the alloy with a fully B2 microstructure shows an ultralow elongation (∼5%) and a typical brittle fracture characteristic.For Ti–22Al–25Nb alloy, α2 phase dissolves gradually and the average grain size of B2 phase increases with increasing solution temperature and time. The pinning of some α2 particles at the B2 grain boundaries results in abnormal grain growth (AGG). Furthermore, various microstructure characteristics have significant influence on room temperature tensile properties.
      PubDate: 2017-03-30T04:35:49.507818-05:
      DOI: 10.1002/adem.201700081
       
  • Alloying Effects on the Phase Transformation Behaviors of the Orthorhombic
           and Ordered ω Phases in High Nb–TiAl Alloys 
    • Authors: Xingguo Hu; Jinshan Li, Lin Song, Tiebang Zhang, Hongchao Kou
      Abstract: In this work, alloying effects of Mn, Mo, and Cr on the phase transformation behaviors of the orthorhombic and ordered ω phases in high Nb–TiAl are investigated. Modulated structures are observed in the Mn and Mo-containing alloys indicating that Mn and Mo cannot hinder the formation of the orthorhombic phase while Cr hinders the formation of the orthorhombic phase completely. For the ordered ω phases, small ordered ω particles are observed in the Mn-containing alloy. Though Mn cannot hinder the formation of the ordered ω phases, the formation temperature of which is decreased to 600 °C. No ordered ω phases are observed in the Mo and Cr-containing alloys. Two percent of Mo and Cr hinder the formation of the ordered ω phases completely. The stabilization effect of Mn, Mo, and Cr on βo phase is mainly a thermodynamic effect.Alloying effects of Mn, Mo, and Cr on the phase transformation behaviors of the orthorhombic and ordered ω phases are investigated. Mn and Mo cannot suppress the formation of the orthorhombic phase. Only in the 2Mn alloy are the ordered ω phases observed. The stabilization effect on the βo phase is concluded to be a thermodynamic effect.
      PubDate: 2017-03-30T04:30:33.033534-05:
      DOI: 10.1002/adem.201700040
       
  • Effect of Severe Plastic Deformation and Subsequent Silicon Spheroidizing
           Treatment on the Microstructure and Mechanical Properties of an
           Al–Si–Mg Alloy 
    • Authors: Nima Haghdadi; Abbas Zarei-Hanzaki, Megumi Kawasaki, Andre B. Phillion, Peter D. Hodgson
      Abstract: This study investigated the synergetic effects of severe plastic deformation and subsequent heat treatment on the characteristics of an A356 alloy. The severe deformation by accumulative back extrusion (ABE) at 300 °C substantially refined the α–Al primary phase and Si particles, but did not homogeneously redistribute the Si particles. ABE also improved the strength but did not enhance the ductility. To make a compromise between strength and ductility, a subsequent heat treatment at 540 °C was carried out. It was shown that severe plastic deformation substantially accelerated the silicon spheroidization. Heat treatment increased the ductility of the material from ∼8% (in the deformed condition) to ∼15%. This was discussed with emphasis on restoration of the matrix, spheroidization of the Si particles, and redistribution of the Si particles within the α–Al matrix.In order to make a compromise between strength and ductility, a subsequent heat treatment is carried out on a severely deformed A356 alloy. Heat treatment for 2 min at 540 °C changes the fracture mode from brittle to ductile, makes cracks to propagate intragranularly, and, in turn, enhances the ductility of the material from ≈8% to ≈15%.
      PubDate: 2017-03-28T07:15:28.635731-05:
      DOI: 10.1002/adem.201700064
       
  • Evaluation of Textural Effect on the Rollability of AZ31 Alloys by
           Wedge-Shaped Sample Design 
    • Authors: Renlong Xin; Maoyin Wang, Zhe Liu, Xingpin Chen, Guangjie Huang, Qing Liu
      Abstract: This paper aims to compare the textural effect on the rollability of Mg alloy sheets at different temperatures. Wedge-shaped AZ31 alloy plates with two kinds of initial textures are designed and rolled at five different temperatures. Then, the rollability under different conditions can be evaluated by observing the development of edge-cracks. The results show that the initial texture has little influence on the single-pass rollability at low temperatures (100 and 150 °C), while the influence is significant for rolling above 150 °C. Schmid factor and in-grain misorientation axis analyses revealed that the textural effect on the activation of prismatic glide accounted for the observed distinct rollability at elevated temperatures.Wedge-shaped AZ31 alloy plates with two kinds of initial textures are designed and rolled at five different temperatures. Then, the rollability under different conditions can be evaluated by observing the development of edge-cracks. It shows that the initial texture has little influence on the single-pass rollability at low temperatures, while the influence was significant for rolling above 150 °C.
      PubDate: 2017-03-24T05:15:14.36925-05:0
      DOI: 10.1002/adem.201700035
       
  • A High Strength Ti–SiC Metal Matrix Composite 
    • Authors: Khandaker Mezanur Rahman; Vassili A. Vorontsov, Stephen. M. Flitcroft, David Dye
      Abstract: A SiC reinforced Ti-5Al-5Mo-5V-3Cr matrix metal matrix composite is developed. Monolithic blocks of alloy are hot rolled via pack rolling to produce foils for MMC panel fabrication. These are consolidated using hot isostatic pressing and solution treated and aged for optimum strength. The panels exhibited a strength of 2 GPa in tension and 3.5 GPa in compression, compared to the aerospace steel 300M, which has a tensile strength of 1.69 GPa. The fatigue performance of the material exceeded that of MMCs developed using Ti-21S or Ti-6Al-4V matrices. Finally, the reaction zone between the SiC and matrix is examined, revealing the presence of TiC.A metal matrix composite is produced using a titanium matrix and silicon carbide reinforcement. A cheaper foil fibre foil layup method is used. The resultant material had a tensile strength in excess of 2GPa with excellent fatigue properties.
      PubDate: 2017-03-22T03:40:43.588538-05:
      DOI: 10.1002/adem.201700027
       
  • Nano-Hydroxyapatite and TiO2 Bioactivated Polymer for Implant Applications
    • Authors: Suzan Bsat; Jennifer McTaggart, Xiao Huang
      Abstract: Polymers have been successfully used for implant applications, however, challenges remain as their design requires a delicate balance between mechanical, chemical, and physical properties to ensure cell survival and tissue formation. Additive manufacturing techniques, such as SLA, offer the opportunity to achieve desired physical and mechanical properties because of the precision and control over architecture. Such control allows manipulation over the distribution of mechanical properties throughout the implant. PMA/HA and PMA/TiO2 solid and porous structures are, therefore, manufactured using room temperature SLA techniques. HA and TiO2 are added to the polymer for bio-functionalizing purposes. The apatite forming ability of the samples are evaluated using HBSS immersion. All PMA and PMA/TiO2 samples does not show any bioactivity in terms of apatite formation, although limited amounts of CaO is found on PMA surfaces. PMA/HA samples demonstrate bioactivity with newly formed apatite formation observed after 3 and 5 week HBSS immersion.PMA, PMA/TiO2, and PMA/HA polymer structures for implant applications are fabricated using SLA technique. Following HBSS immersion, PMA/HA composite has an abundance of calcium phosphate mineral formation as compared to PMA and PMA/TiO2, based on SEM and EDS results. Future studies will focus on optimizing PMA/HA polymer structure to obtain desired physical and mechanical properties.
      PubDate: 2017-03-20T08:21:01.908749-05:
      DOI: 10.1002/adem.201600727
       
  • Effect of Ti and Zr Combined Modification on Microstructures and
           Mechanical Properties of Mg95Y2.5Zn2.5 Alloy Containing LPSO and W
           Phases 
    • Authors: Shouzhong Wu; Yanbin Ma, Jinshan Zhang, Chunxiang Xu, Xiaofeng Niu, Wei Liu
      Abstract: In order to develop a high performance Mg–Y–Zn alloy containing LPSO phase in the condition of lower Y/Zn atomic ratio, the effect of Ti and Zr on microstructures and mechanical properties of Mg95Y2.5Zn2.5 alloy was investigated. Although the α-Mg grains can be refined by adding Ti and Zr separately, the best refinement effect can be obtained by the combined addition of them. More importantly, the formation of LPSO phase was promoted by adding them in as-cast Mg95Y2.5Zn2.5 alloy. Meanwhile, the growth model of W phase was transformed from divorced eutectic to cooperative eutectic. In this case, the LPSO/W interface became continuous, which degraded the mechanical properties of as-cast alloys. After extrusion, the increased LPSO phase caused by adding Ti and Zr greatly improved the strength of as-extruded alloy.Mg93.1Y2.5Zn2.5Ti1.6Zr0.3 alloy has the best refinement effect due to the combined addition of Ti and Zr. Meanwhile, Ti and Zr promote the formation of LPSO and change the growth model of W phase. The increased LPSO phase does not enhance mechanical properties of as-cast alloy, but rather greatly improves mechanical properties of as-extruded alloy.
      PubDate: 2017-03-16T06:51:24.521429-05:
      DOI: 10.1002/adem.201600839
       
  • Microstructure and Crystallography of α Phase Nucleated Dynamically
           during Thermo-Mechanical Treatments in Metastable β Titanium Alloy 
    • Authors: Jiangkun Fan; Jinshan Li, Yudong Zhang, Hongchao Kou, Lionel Germain, Nathalie Siredey-Schwaller, Claude Esling
      Abstract: The α phase nucleated dynamically during the thermo–mechanical coupling process in titanium alloy is really interesting but difficult to sufficiently ascertain. In the present work, the α phase nucleation behavior, the orientation relationship between α/β as well as the phase transformation kinetics during hot deformation of Ti-5553 alloy were investigated in-depth. Results reveal that the “necklace” microstructure formed. The Burgers orientation relationship between α/β phases has been destroyed gradually. The β  α phase transformation is obviously retarded during the hot compression due to the competitive effect of softening process (dynamic recovery/recrystallization). These results could provide valuable reference for process optimization and the microstructural evolution controlling.The dynamic nucleation and evolution of α phase during hot deformation is totally different from heat treatment. The “necklace” microstructure forms and the Burgers orientation relationship between α/β is destroyed. There is a competitive mechanism between β  α phase transformation and DRV/DRX.
      PubDate: 2017-03-15T09:35:37.966941-05:
      DOI: 10.1002/adem.201600859
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.158.25.146
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016